Most houses in Japan are small. As you may expect, houses in the countryside are bigger than those in the city, and older houses also tend to be bigger, but generally speaking most houses are pretty small.
It’s not only houses. At my last apartment in the States, I was paying considerably less than I am now but yet my current apartment is only about a quarter of the size of that one. Okazaki is hardly a large city and prices are even higher in places like Tokyo.
But this isn’t to say all houses are tiny. The photo below shows a relatively big one I came across during one of my walks. Not only is the house big, but look at all that land. Kind of rare for Japan. There is a huge garage to the right that I cut out of the photo. The house right beside it has an equally large space in front of it.
I must have stumbled upon the doctors neighborhood.