An image forming apparatus comprising: a first image bearing member configured to have a toner image formed thereon; a second image bearing member configured to have a toner image formed thereon which is different in color from the toner image formed on said first image bearing member; a transfer member configured to have the toner image formed on said first image bearing member and the toner image formed on said second image bearing member transferred thereon in superimposed relation; contact means configured to bring said transfer member into contact with said first image bearing member and said second image bearing member; phase difference detection means (103a, 103d, 204) configured to detect a rotational phase difference between said first image bearing member and said second image bearing member; and control means (201, 204) configured to perform phase control for bringing a phase of said first image bearing member and a phase of said second image bearing member into predetermined relation, based on the rotational phase difference detected by said phase difference detection means (103a, 103d, 204), characterized in that said control means (201, 204) performs the phase control in a state where said transfer member does not contact with said first image bearing member and said second image bearing member in a case where the rotational phase difference is out of a predetermined range, and performs the phase control in a state where said transfer member contacts with said first image bearing member and said second image bearing member by said contact means in a case where the rotational phase difference is within the predetermined range. a first image bearing member configured to have a toner image formed thereon; a second image bearing member configured to have a toner image formed thereon which is different in color from the toner image formed on said first image bearing member; a transfer member configured to have the toner image formed on said first image bearing member and the toner image formed on said second image bearing member transferred thereon in superimposed relation; contact means configured to bring said transfer member into contact with said first image bearing member and said second image bearing member; phase difference detection means (103a, 103d, 204) configured to detect a rotational phase difference between said first image bearing member and said second image bearing member; and control means (201, 204) configured to perform phase control for bringing a phase of said first image bearing member and a phase of said second image bearing member into predetermined relation, based on the rotational phase difference detected by said phase difference detection means (103a, 103d, 204), characterized in that said control means (201, 204) performs the phase control in a state where said transfer member does not contact with said first image bearing member and said second image bearing member in a case where the rotational phase difference is out of a predetermined range, and performs the phase control in a state where said transfer member contacts with said first image bearing member and said second image bearing member by said contact means in a case where the rotational phase difference is within the predetermined range.