An angle detector includes a rotating member, a housing, a detector and an urging member. The rotating member is rotatable with a shaft inserted therethrough. The housing rotatably supports the rotating member. The detector detects a rotating angle of the rotating member with respect to the housing. The urging member urges the rotating member in a rotating direction of the rotating member. An engagement portion is provided on the housing. An engaged portion is provided on the rotating member. The engaged portion is adapted to be brought into engagement with the engagement portion by urged by the urging member.