An image forming apparatus, comprising: a conveyer that conveys continuous paper through a conveying path; a detector that detects a mark on the continuous paper conveyed by the conveyer; an image former that is provided on a subsequent stage side of the detector and forms an image on the continuous paper; and a controller that causes the image former to start forming an image according to a position setting for forming an image on the continuous paper using the image former after a mark on the continuous paper is detected, wherein the controller adjusts the position setting on the basis of a start position determined according to an image formation state, wherein the image formation state is a state in which an overprinting or a post-suspension restart printing is performed, a first set value is set as a control parameter for the overprinting, a second set value is set as a control parameter for the post-suspension restart printing, the controller controls the overprinting and the post-suspension restart printing, an image formation position at each time the detector detects the mark is set on the basis of the first set value in the overprinting, and a first image formation position at a time of print restart is set on the basis of the second set value in the post-suspension restart printing, wherein in a case where the controller causes the overprinting to be executed, the controller adjusts the start position of an image according to a position of a corresponding mark detected by the detector and the first set value at each time an image is formed on the continuous paper, and characterized in that in a case where the controller causes the post-suspension restart printing to be executed, the controller adjusts the start position of the first image according to a position of a mark of a last image (I_last) that has been printed and pulled back to the upstream side of its start position before restart among marks detected by the detector and the second set value. a conveyer that conveys continuous paper through a conveying path; a detector that detects a mark on the continuous paper conveyed by the conveyer; an image former that is provided on a subsequent stage side of the detector and forms an image on the continuous paper; and a controller that causes the image former to start forming an image according to a position setting for forming an image on the continuous paper using the image former after a mark on the continuous paper is detected, wherein the controller adjusts the position setting on the basis of a start position determined according to an image formation state, wherein the image formation state is a state in which an overprinting or a post-suspension restart printing is performed, a first set value is set as a control parameter for the overprinting, a second set value is set as a control parameter for the post-suspension restart printing, the controller controls the overprinting and the post-suspension restart printing, an image formation position at each time the detector detects the mark is set on the basis of the first set value in the overprinting, and a first image formation position at a time of print restart is set on the basis of the second set value in the post-suspension restart printing, wherein in a case where the controller causes the overprinting to be executed, the controller adjusts the start position of an image according to a position of a corresponding mark detected by the detector and the first set value at each time an image is formed on the continuous paper, and characterized in that in a case where the controller causes the post-suspension restart printing to be executed, the controller adjusts the start position of the first image according to a position of a mark of a last image (I_last) that has been printed and pulled back to the upstream side of its start position before restart among marks detected by the detector and the second set value.