The Real Estate section {Feb. 13} carried a picture of a Tokyo "mini-apartment" with dimensions that measure three feet wide, eight feet deep and seven feet high. Hundreds of such apartments have been built, according to the picture's caption, and there are no vacancies.

My first reaction was one of amazement that anyone would rent such a small space. But when I thought about it longer, I began to wonder if similar mini- apartments might not be a partial answer for the homeless of the metropolitan area.

Some of those who live on the streets, I understand, hold jobs, but do not earn enough to be able to afford conventional housing in the Washington area. Perhaps they could afford a mini- apartment, however. In Tokyo, where space is very dear, such apartments rent for $225 a month. In Washington, maybe they could be rented for $150 or so a month. Such a space would give a single person a warm place to sleep and a place to be clean and to store a few belongings. But most of all, it would give him the dignity of living in an earned space.

Current "solutions" to the problem of housing have not solved it. This would be an entirely new approach. Perhaps there is a building that the District -- or a private builder of vision and daring -- could renovate into mini-apartments, including clusters of bathroom, laundry and minimal kitchen facilities. If the mini-apartments were available to those who earn some money, more of the existing shelter space could be freed for those who earn none. Isn't it worth a try? MILDRED M. THOMAS Alexandria