To provide a balcony draining device which prevents dripping of rainwater or condensation liquid water that has not been introduced into a rain gutter, from a deck.

According to the balcony draining device, the rain gutter 15 opening upward is sequentially arranged under a floor joist bearer 4 from a lower side of a left end beam 2 to a lower side of a right end beam 2, and an eave soffit plate 17 extending along a lower side of each floor joist 11 of the deck in a manner declining from a lower surface of a front girder to an opening surface of the rain gutter, is sequentially arranged from a lower surface of the left end beam to a lower surface of the right end beam. Thus rainwater or condensation liquid water dripping from the deck or the floor joists, and rainwater or condensation liquid water dripping from the floor joist bearer, the end beams, and the front girder are all received by the eave soffit plate and converged to the rain gutter 15, and the rainwater or the condensation dew converged to the rain gutter is drained via a downpipe 25 to the ground.