diff --git a/src/infra/repository/nita.js b/src/infra/repository/nita.js
index 8f60997..db52db2 100644
--- a/src/infra/repository/nita.js
+++ b/src/infra/repository/nita.js
@@ -109,5 +109,22 @@ export const postgresNitaRepository = () => {
       `;
       return Number(results[0].count);
     },
+    async selectRival(executorDiscordId, rivalDiscordId) {
+      const results = await sql`
+        SELECT
+          nita1.track_code,
+          nita1.milliseconds AS executor_milliseconds,
+          nita2.milliseconds AS rival_milliseconds
+        FROM (SELECT * FROM nita WHERE discord_user_id = ${executorDiscordId}) AS nita1
+        INNER JOIN (SELECT * FROM nita WHERE discord_user_id = ${rivalDiscordId}) AS nita2
+          ON nita1.track_code = nita2.track_code
+        ORDER BY nita1.milliseconds - nita2.milliseconds
+      `;
+      return results.map((row) => ({
+        trackCode: row.track_code,
+        executorMilliseconds: row.executor_milliseconds,
+        rivalMilliseconds: row.rival_milliseconds,
+      }));
+    },
   };
 };
diff --git a/src/slash-command/rival.js b/src/slash-command/rival.js
new file mode 100644
index 0000000..91a7e7e
--- /dev/null
+++ b/src/slash-command/rival.js
@@ -0,0 +1,73 @@
+// @ts-check
+import { SlashCommandBuilder } from 'discord.js';
+import { searchTrack } from '../const/track.js';
+import { displayMilliseconds } from '../util/time.js';
+
+/** @type { import('../types').SlashCommand } */
+export default {
+  data: new SlashCommandBuilder()
+    .setName('rival')
+    .setDescription('サーバー内のユーザーと記録を比較します')
+    .addUserOption((option) =>
+      option.setName('rival').setDescription('比較対象').setRequired(true),
+    ),
+  execute: async (interaction, nitaRepository) => {
+    if (!interaction.guild) {
+      if (!interaction.inGuild()) {
+        throw new Error(
+          'サーバー内で実行してください。rivalコマンドはDMやグループDMでは実行できません。',
+        );
+      }
+      // https://github.com/discordjs/discord.js/blob/main/packages/discord.js/src/structures/BaseInteraction.js#L180-L182
+      // https://github.com/moeyashi/discord-mk8d-nita-record/issues/78
+      // https://scrapbox.io/discordjs-japan/%E3%83%9E%E3%83%8D%E3%83%BC%E3%82%B8%E3%83%A3%E3%83%BC%E3%81%8B%E3%82%89%E3%83%87%E3%83%BC%E3%82%BF%E3%82%92%E5%8F%96%E5%BE%97%E3%81%99%E3%82%8B
+      // interaction.guildはキャッシュから取得しているしているため、interaction.guildがfalsyでinteraction.guildIdがtruthyの場合はfetchして取得する
+      await interaction.client.guilds.fetch(interaction.guildId);
+      if (!interaction.guild) {
+        throw new Error(
+          '不明なエラー：サーバーが見つかりませんでした。スクショして連絡してもらえたらありがたいです！',
+        );
+      }
+    }
+
+    const userQuery = interaction.options.getUser('rival');
+    if (!userQuery) {
+      throw new Error('比較対象を指定してください');
+    }
+
+    await interaction.deferReply();
+
+    const tracks = await nitaRepository.selectRival(
+      interaction.user.id,
+      userQuery.id,
+    );
+    /** @type {import('discord.js').InteractionReplyOptions} */
+    const res = {
+      content: `VS ${userQuery.displayName || userQuery.username}`,
+    };
+    if (tracks.length === 0) {
+      res.content = res.content + '\n\n記録がありません';
+    } else {
+      /** @type {import('discord.js').APIEmbed[]} */
+      const embeds = [];
+      res.embeds = tracks.reduce(
+        (pv, { trackCode, executorMilliseconds, rivalMilliseconds }, i) => {
+          const track = searchTrack(trackCode);
+          if (i % 25 === 0) {
+            pv.push({
+              fields: [],
+            });
+          }
+          const diffRival = executorMilliseconds - rivalMilliseconds;
+          pv[pv.length - 1].fields?.push({
+            name: track?.trackName || '',
+            value: `${displayMilliseconds(executorMilliseconds)} VS ${displayMilliseconds(rivalMilliseconds)} ${diffRival / 1000}秒`,
+          });
+          return pv;
+        },
+        embeds,
+      );
+    }
+    await interaction.followUp(res);
+  },
+};
diff --git a/src/types.d.ts b/src/types.d.ts
index 9eebee8..bd7e1d2 100644
--- a/src/types.d.ts
+++ b/src/types.d.ts
@@ -39,6 +39,10 @@ export type NitaRepository = {
     trackCode: string,
     discordMembers: GuildMember[]
   ) => Promise<number>;
+  selectRival: (
+    executorDiscordId: string,
+    rivalDiscordId: string 
+  ) => Promise<{ trackCode: string; executorMilliseconds: number; rivalMilliseconds: number; }[]>;
 };
 
 // 参考 https://typescriptbook.jp/reference/functions/overload-functions#%E3%82%A2%E3%83%AD%E3%83%BC%E9%96%A2%E6%95%B0%E3%81%A8%E3%82%AA%E3%83%BC%E3%83%90%E3%83%BC%E3%83%AD%E3%83%BC%E3%83%89