There is provided a technique in which when an image forming processing with toners of plural colors is performed, a residual toner on a transfer-receiving member to which toner images are transferred by plural image forming units is not discarded, but is reused as a black toner, and a deterioration in picture quality due to a change in color tone of the black toner is prevented. An image forming apparatus is for performing an image forming processing by plural image forming units to form toner images of colors different from each other on a transfer-receiving member moved in a specified direction, and includes a toner collecting unit to collect toners remaining on the transfer-receiving member, a ratio judgment unit to judge a mixing ratio of toners of plural colors included in the toners collected by the toner collecting unit, and a toner replenishing unit to replenish an insufficient color toner to the toners collected by the toner collecting unit based on the mixing ratio judged by the ratio judgment unit so that the mixing ratio becomes a specified ratio.