Spend any decent amount of time walking around Tokyo -- that is, non-tourist Tokyo -- and you'll soon realize that the Japanese approach to zoning differs considerably from the American approach. This is most noticeable in the intermingling of businesses (light industrial, wholesale, and other small mom and pop businesses), and residences (both apartments and single-family homes). (This article is a good primer on Japanese zoning laws and how they differ from the US.)
Here we have a small business of which type I forget now, although the washing machine outside might provide a clue. I imagine a business washing uniforms, tablecloths and the like for izakaya chains. Or alternatively it's a small print shop that moved its washing machine outside to make room for another printer or cutter. Next door is a tonkatsu restaurant, and what looks to be a small office building beyond that.