An image forming apparatus comprising: a rotatable belt; a first image bearing member; first image forming means for forming an electrostatic latent image and a toner image on said first image bearing member; a second image bearing member disposed downstream of said first image bearing member with respect to a rotational direction of said belt; second image forming means for forming an electrostatic latent image and a toner image on said second image bearing member; transferring means for transferring, onto a belt or onto a recording material carried on said belt, the toner image formed on said first image bearing member and a toner image formed on said second image bearing member; feeding direction calculating means for calculating a moving direction of a predetermined point on said belt; an executing portion for executing an operation in a correcting mode in which a positional relation between an adjustment toner image transferred onto said belt from said first image bearing member and adjustment toner image transferred onto said belt from said second image bearing member is detected, and a writing starting position of the electrostatic latent image to be formed on at least one of said image bearing members is determined on the basis of a result of the detection; and characterised by changing means for changing the writing starting position determined by said correcting mode on the basis of a difference between the moving direction calculated by said feeding direction calculating means during the operation in the correcting mode and the moving direction calculated by said feeding direction calculating means during image formation based on an inputted image formation signal. a rotatable belt; a first image bearing member; first image forming means for forming an electrostatic latent image and a toner image on said first image bearing member; a second image bearing member disposed downstream of said first image bearing member with respect to a rotational direction of said belt; second image forming means for forming an electrostatic latent image and a toner image on said second image bearing member; transferring means for transferring, onto a belt or onto a recording material carried on said belt, the toner image formed on said first image bearing member and a toner image formed on said second image bearing member; feeding direction calculating means for calculating a moving direction of a predetermined point on said belt; an executing portion for executing an operation in a correcting mode in which a positional relation between an adjustment toner image transferred onto said belt from said first image bearing member and adjustment toner image transferred onto said belt from said second image bearing member is detected, and a writing starting position of the electrostatic latent image to be formed on at least one of said image bearing members is determined on the basis of a result of the detection; and characterised by changing means for changing the writing starting position determined by said correcting mode on the basis of a difference between the moving direction calculated by said feeding direction calculating means during the operation in the correcting mode and the moving direction calculated by said feeding direction calculating means during image formation based on an inputted image formation signal.