An inkjet printer, including an inkjet head, a conveyer unit to convey a recording medium in a conveying direction, a position detecting unit to detect a position of the recording medium along the conveying direction, a wave shape generating mechanism to deform the recording medium into a predetermined wave shape along a direction orthogonal to the conveying direction, a gap information storing device to store gap information related to a gap between an ink discharging surface of the inkjet head and the recording medium, and a correcting device to correct the gap information according to a position of the recording medium along the conveying direction, is provided.