An image forming apparatus includes an image bearing member, a first conductive member, a bias application device, and a control portion, and performs image formation on a surface of the image bearing member while making the image bearing member rotate. The image forming apparatus is capable of executing a heating-up mode in which, at the time of non-image formation, in a state where the image bearing member is made to rotate at a velocity lower than that used at the time of image formation, an alternating current bias having a frequency higher than that used at the time of image formation and a peak-to-peak value twice or more as large as a discharge start voltage between the first conductive member and the image bearing member is applied to the first conductive member to cause a surface of the image bearing member to be heated up.