To provide a unit building enabling an inclined roof of large size including a shed roof to be easily constructed.

On a first floor, a trapezoid-shaped unit 3 is placed with an inclined surface 3a facing an exterior side and is bounded posteriorly by a standard unit 2. Among the standard units 2 on a second floor, the standard unit 2 arranged most exterior side is positioned further exterior side than the trapezoid-shaped unit 3. An inclined roof 1 is constructed along the inclined surface 3a of the trapezoid-shaped unit 3 from an upper portion of the standard unit 2 on the first floor to the upper portion of the standard unit 2 positioned at the exterior side on the second floor. An upper end of the inclined roof 1 is supported by an upper framework section 5 formed above the standard unit 2 on the second floor and a lower end of the inclined roof 1 is supported by a lower framework section 6 formed above the standard unit 2 positioned at the exterior side on the first floor.