To provide a draining device which can collect dust and hairs in drainage at one spot without sticking the dust and hairs to a collecting portion, can carry out self-cleaning of the interior thereof, and has an arbitrarily designed shape of the collecting portion.

The draining device is formed of: a drain port 1 into which drainage flows; a case-shaped box body 2 having the drain port 1 formed in an upper portion thereof; a branch pipe 3 for leading drainage from another channel into the box body 2; a case-shaped trap room 4 located on a downstream side of the box body 2; a connection portion 5 communicating between the box body 2 and the trap room 4, and connecting the former and the latter to each other; a discharge port 6 located on a downstream side of the trap room 4, for discharging the drainage; a seal water component part 7 forming seal water in cooperation with the discharge port 6 of the trap room 4; and the cage-shaped collecting portion 11 mounted in the drain port 1 in a manner being immersed in the box body 2, for collecting dust in the drainage. Herein the box body 2 has a stream restriction device 14 formed therein, which defines a direction from the branch pipe 3 to the collecting portion 11 so as to lead the stream into the box body 2.