To provide a unit building reduced in construction cost and having originality by utilizing the shape of a roof unit and also providing an easily constructed roof structure.

This unit building 2 is formed by plural building units 4a, 6a and a roof unit 8. The building units 4a, 6a are box-shaped units. The roof unit 8 is provided with a pair of sloped roof surfaces 8b, 8c having the ridge part 8a on the top, and triangular transverse walls 8d, 8e on both sides of the sloped roof surfaces 8b, 8c, and disposed on the second floor building unit 6a with the ridge part 8a directed along the frontage.