The inkjet printer includes a loading part of a recording medium; a print base for holding the recording medium thereon; a sucking unit for sucking the recording medium on the print base; an image recording unit for recording an image on the recording medium held on the print base by an ink jet recording method; transport units for transporting the recording medium form upstream through downstream of the image recording unit; one or both of medium type detector for determining a type of the recording medium in the loading part, and medium thickness detector for detecting a thickness of the recording medium in the loading part; and suction controller for changing suction force of the sucking unit with respect to the recording medium according to a detection result obtained by one or both of the medium type detector and the medium thickness detector.