To provide a drain structure of a bathroom for preventing a bathroom user from cherishing an unpleasant feeling, by restraining generation of an air inflow sound when there is a large quantity of drain.

A drain trap 6 id arranged in a main drain pipe 5 for draining water outside the bathroom 1 from a bathtub 2 and a washing place 3. A sub-drain pipe 7 for draining water from a place of the bathroom 1 except for the bathtub 2 and the washing place 3, is connected to a side surface of the drain trap 6. An elbow 8 is installed in an outflow port to a side surface of the drain trap 6 of the sub-drain pipe 7. An opening of the elbow 8 forming an outflow port to the drain trap 6 of the sub-drain pipe 7, is arranged downward in the vicinity of a bottom surface of the drain trap 6.