SENSING DEVICE AND BICYCLE PROVIDED WITH SENSING DEVICE

A sensing device 20 that detects the rotation of a wheel 4 of a bicycle 1, the sensing device 20 including a mobile-side sensing body 22 provided on the wheel 4, and an immobile-side sensing body 23 provided on a chain stay 13, the immobile-side sensing body 23 including a mounting section 29 attached to the chain stay 13, a sensor 30 that detects the mobile-side sensing body 22 crossing the immobile-side sensing body 23, and a supporting section 31 that supports the sensor 30, the sensor 30 being movable in a first direction A that increases or reduces a distance D between the mounting section 29 and the sensor 30, the sensor 30 including a fixing member 38 that fixes the sensor 30 to the supporting section 31.