An image forming apparatus includes a toner image forming portion, an information acquisition portion and a control portion. The control portion carries out processes (i) and (ii). In the process (i), the control portion causes the toner image forming portion to form, as a test image, at least either one of a toner image of single dot and a toner image of dot line consisting of single dots arranged in one or more rows in a predetermined direction, and then causes the information acquisition portion to acquire optical information on the formed test image. In the process (ii), the control portion corrects a condition for forming the toner image in the toner image forming portion, based on a state (size, concentration distribution, edge shape) of the test image obtained from the optical information acquired by the information acquisition portion.