(/) **** is the most suitable and natural word in this context. It can be used safely regardless of whether the restaurant is causal or expensive, Japanese-style or Western-style.
You can also use or (see: What is the difference between , , , and ?) if you really want to be specific. If you know the restaurant is categorized as (the most expensive type), you can use it, too. But in my opinion, () is the most natural when you just want to say "(this) restaurant" generically without worrying about details. See this answer, too.
( is a "beautifying" prefix which isn't strictly necessary, but most people keep it when they want to speak politely.)
**EDIT:** "Generic Japanese-style restaurants" is perhaps or , but people usually don't imagine sushi restaurants, unagi-ya and ramen shops with this word. If you want to refer to everything like these, you may have to say or something.