An accelerator device includes: an accommodation part; a rotation shaft having a first end and a second end that are supported by the accommodation part; a pedal part having a first end fixed to the rotation shaft and a second end to be pressed by a driver of a vehicle in an open direction; a return mechanism part biasing the rotation shaft to be rotated in a close direction opposite from the open direction; and a seal member restricting a foreign matter from entering an interior space of the accommodation part.