An image forming apparatus includes an image bearing member, a transfer member, a moving portion, a driving portion, a voltage applying portion, a first detecting portion, and a second detecting portion. On the basis of a detection result of the first detecting portion when a first test voltage is applied to the transfer member by the voltage applying portion, the second detecting portion sets a second test voltage. The second detecting portion detects a position of the transfer member on the basis of a detection result of a current value by the first detecting portion acquired when the second test voltage is applied to the transfer member by the voltage applying portion.