A conveyance device including an upstream roller that supplies a sheet medium to be processed to a conveyance path; a downstream roller that conveys the supplied medium to a processing position; and a control unit that, in order to convey the sheet medium at a constant speed, controls driving the upstream roller and the downstream roller using the constant speed as a target speed. The control unit changes the target speed of the upstream roller to eliminate a conveyance difference, which is the difference between the length of media conveyed by the upstream roller and the length of media conveyed by the downstream roller from the start of the conveyance operation, based on the conveyance difference in each conveyance operation.