宇宙人なんですけど。

From Author Wars - https://authorwars.com/publications/yu-zhou-ren-nandesukedo-551824.html

Overview:

Title: 宇宙人なんですけど。
Author: 榊一郎
Year: 2007
ISBN-10: 9784757739154
Publisher: エンターブレイン
Pages: 274
Binding: Paperback
Type: Novel
Title Reference: 宇宙人なんですけど。
Notes: Data from Amazon.co.jp
Cover artist per cover credit
Title transliterates as "Uchuujin Nandesukedo." (Actually, I'm Sure It's an Alien.)