PROBLEM TO BE SOLVED: To provide a drain trap which reduces time and effort to maintain sanitary.SOLUTION: A drain trap 100 includes: a power generation part 30 where power is generated by force of water flowing inside a trap body 10 and a light source 40 irradiating ultraviolet rays to the inside of the drain trap 100 by using electric power generated in the power generation part 30. The drain trap 100 is rotatably supported to the trap body 10, and includes a bell trap 20 having a rotary wing 26 which generates the force of the rotation by the force of the water flowing inside the trap body 10. The power generation part can generate the power by turning force which the rotary wing 26 generates. The power generation part 30 includes a power storage part, and the power storage part stores the electrical power generated in the power generation part. The stored electrical power can be supplied to the light source 40 to irradiate the ultraviolet light.
