diff --git a/packages/client/src/routes/orgs/[orgId]/settings/+page.svelte b/packages/client/src/routes/orgs/[orgId]/settings/+page.svelte
index 2e2cbc3..5f5630d 100644
--- a/packages/client/src/routes/orgs/[orgId]/settings/+page.svelte
+++ b/packages/client/src/routes/orgs/[orgId]/settings/+page.svelte
@@ -1,6 +1,6 @@
 <script lang="ts">
   import { api, type Id } from "@packages/convex";
-  import { useQuery } from "convex-svelte";
+  import { useConvexClient, useQuery } from "convex-svelte";
   import { page } from "$app/stores";
   import { useMutation } from "~/lib/useMutation.svelte.ts";
 
@@ -14,6 +14,7 @@
   }));
   const updateOrganization = useMutation(api.organizations.update);
   const removeMember = useMutation(api.organizations.removeMember);
+  const convex = useConvexClient();
 
   let isEditing = $state(false);
   let editForm = $state({
@@ -55,6 +56,41 @@
       }
     }
   }
+
+  async function addMember() {
+    let email = prompt("追加するメンバーのメールアドレスを入力してください");
+    if (!email?.trim()) return;
+
+    if (members.data) {
+      for (const m of members.data) {
+        if (m.user?.email === email) {
+          alert("そのメンバーはもう存在します");
+          return;
+        }
+      }
+    }
+    const users = await convex.query(api.users.getUsersByEmail, { email });
+    if (!users.length) {
+      alert("ユーザーが見つかりませんでした");
+      return;
+    }
+    if (users.length > 1) {
+      alert(
+        "同じメールアドレスで登録されている人物が複数確認されました。開発者に報告してください。",
+      );
+      return;
+    }
+    let message = `以下のユーザーが見つかりました\n${users[0]?.name}\n組織に追加しますか？`;
+
+    const answer = confirm(message);
+    if (answer && users[0]) {
+      convex.mutation(api.organizations.addMember, {
+        organizationId: organizationId,
+        userId: users[0]._id as Id<"users">,
+        permission: "member",
+      });
+    }
+  }
 </script>
 
 <div class="container mx-auto p-6">
@@ -143,7 +179,9 @@
         <div class="mb-4 flex items-center justify-between">
           <h2 class="card-title">メンバー</h2>
           {#if organization.data?.permission === "admin"}
-            <button class="btn btn-primary btn-sm"> メンバーを追加 </button>
+            <button class="btn btn-primary btn-sm" onclick={addMember}>
+              メンバーを追加
+            </button>
           {/if}
         </div>
 
diff --git a/packages/convex/src/convex/users.ts b/packages/convex/src/convex/users.ts
index 757267f..e8f4d6e 100644
--- a/packages/convex/src/convex/users.ts
+++ b/packages/convex/src/convex/users.ts
@@ -64,3 +64,15 @@ export const getUserNicknames = query({
     return userNicknames;
   },
 });
+
+export const getUsersByEmail = query({
+  args: {
+    email: v.string(),
+  },
+  handler: async (ctx, args) => {
+    return await ctx.db
+      .query("users")
+      .filter((q) => q.eq(q.field("email"), args.email))
+      .collect();
+  },
+});