A platen includes a plurality of supporting portions capable of supporting a sheet; negative pressure chambers, to which a negative pressure is supplied, so as to suck a sheet facing the supporting portions to the supporting portions; and an ink receiver that receives ink ejected from a printhead to the outside of the sheet supported by the supporting portions. The plurality of supporting portions are arranged in a sheet width direction transverse a sheet conveyance direction. The plurality of negative pressure chambers are disposed in a manner corresponding to the plurality of supporting portions, respectively.