Why is Lawson in Shin-Ōkubo asking me for a guarantor (保証人) for a part-time job?

I called a Lawson in Shin-Ōkubo to apply for a baito, and the manager told me I’d need to provide a guarantor (保証人).

I’ve worked at other combini before and never once had to do this. Usually it’s just ID and bank details.

I'm just a bit confused because it's the first time I've ever been asked such a thing