To provide a building with a balcony drain gutter in which a drain gutter spread over a plurality of building units can be provided in a portion of a height of a reinforcement flange even when the reinforcement flange is provided in a floor frame of a balcony frame provided on the plurality of building units in the case where a balcony is surrounded with accessories.

In a pair of floor support upper beams (5, 6), support beams (34a, 34b) are provided which include reinforcement flanges 39 protruding higher than the upper beams (5, 6). In the reinforcement flanges 39, notches 39f are provided in portions corresponding to drain gutters (16, 16a). The drain gutters (16, 16a) provided in a neighboring balcony unit 3 are disposed via the notches 39f.