In Japan as in Belgium the cow house should be constructed as a single-floor-building. As well from the point of view of labour requirement ;and animal health as construction costs the loose house with_ cubicles and concrete slatted floors between the cubicle rows, must be preferred above the stanchion barn, when the size of the herd is 25 or more cows. In Hokkaido the loose house and the stanchion barn should be insulated, the latter more than the former ; in Honshu only the stanchion barn and the roof of the loose house must de insulated (K≦1) . Natural ventilation can give complete satisfaction, when it is well regulated. When constructing a stanchion barn, one should build the strawless type in order to reduce labour requirement. Full attention should be given to all construction details in order to avoid injuries with the cows and save labour.