Also, they say in the case of formal meetings they can't wear casual clothes. For example, sometimes they have to meet with bankers and customers. People in Japanese offices are also trying to be more casual when they come to work. People choose one day of the week for 'Casual Day'. However, this is going on only in some offices because some people say that we have to be careful about our clothes.
Suits are a kind of uniform for businessman, and some people tend to prefer uniforms.
Of course, nobody thinks that they have good clothes. Moreover, another reason is that casual clothes are not suitable for formal situations in business. They have the same problem as office workers in American offices. It may be difficult to introduce casual clothes into Japanese offices because workers have never been expected to have their own taste in clothes. I interviewed several people to find out what they thought about dressing casually.