A workpiece support device includes a shaft rotatable about a shaft rotation axis of the shaft, a first support, a first reciprocating mechanism, and a first connecting rod having one end and another end. The shaft extends along a longitudinal direction of a workpiece. The first support includes a first support roller that is rotatable about a first roller rotation axis orthogonal to the shaft rotation axis and that is configured to contact the workpiece to support the workpiece. The first reciprocating mechanism has one end connected to the first support and is configured to reciprocate in a first expansion-contraction axis direction. The one end of the first connecting rod is rotatably connected to the first support. The another end of the first connecting rod is connected to the shaft such that the another end of the first connecting rod is rotatable together with the shaft.