A medium clamping device includes: a first circularly-moving body having a circumferential surface harder than a recording medium, a longer length in a direction orthogonal to a circularly-moving direction than the recording medium in a first direction; a second circularly-moving body where the recording medium passes between the surfaces of the two circularly-moving bodies in a second direction crossing the first direction; a load applying section applying a load to at least one of the two circularly-moving bodies to clamp the recording medium; a belt member surrounding the surface of at least one of the two circularly-moving bodies, at a place outside an area touching the recording medium when the recording medium passes; and a belt-member-protecting member which is aligned with the belt member in a recording-medium-passing direction, includes a portion closer to a recording-medium-passing path than the belt member to protect the belt member from contacting the recording medium.