A recording material detecting apparatus includes a detecting device and a reference member. The detecting device irradiates a recording material with light and detects the light from the recording material. The reference member has a reference portion detectable by the detecting device in order to correct the output from the detecting device. The reference member is capable of moving from a position where the reference portion is detected by the detecting device. The reference member is moved by the recording material. Since a driving unit such as a motor is not necessary, the cost of the apparatus body can be dramatically reduced, and the apparatus structure can be dramatically simplified.