I don't know what you mean by restaurant license. If it is a certificate such as a restaurant waiter's qualification certificate, although the Labor Bureau has documents requiring certificates, it is not a hard requirement, and it will not affect employment if it is not provided, so the restaurant cannot force employees to handle it; If you don't want to deal with this situation, the restaurant can't force it.
But if you want to do this industry, having this certificate is better than not having a qualification certificate, so it is an extra stepping stone.