A clamper includes: a first clamping member having a first base portion and a first contact portion that is to be in contact with one surface of the workpiece; a second clamping member having a second contact portion that is to be in contact with the other surface of the workpiece; and a clamping member biasing member configured to bias at least one of the first clamping member and the second clamping member in a direction of bringing the first contact portion and the second contact portion closer to each other. The first contact portion has a plurality of plate spring portions extending from the first base portion, the plurality of plate spring portions configured to elastically deform independently from each other to come into contact with the workpiece.