An image recording apparatus includes a conveyance roller which conveys the recording medium, a drive source for rotating the conveyance roller, a print head and a carriage mounted with the print head. The carriage includes an abutment portion. The image recording apparatus further includes a carriage position detector which detects a position of the carriage in a movement direction of the carriage and still further includes a rotating body which rotates in synchronization with the conveyance roller. The rotating body includes a reference portion which protrudes or depresses in the movement direction at a predetermined rotation phase of the rotating body and abut with the reference portion. Moreover, the image recording apparatus includes an origin determination section which, based on a result of the detection by the carriage position detector, determines an origin position of a rotation phase of the conveyance roller.