To provide a workpiece conveying device which efficiently performs workpiece conveying work using first and second pallets, and also performs workpiece conveying work using only either of the pallets.

A machining table 15 is supported on an upper face of a bed 12 in a reciprocating manner in a Y-axis direction along a guide rail 13 for the table. The first and second pallets 22, 23 are supported in a reciprocating manner in an X-axis direction along first to third pallet guide rails provided on the upper faces of frames disposed on both right and left sides of the machining table 15, and on the upper face of the machining table 15. First and second driving mode switching mechanisms 41A, 41B are provided for switching the first pallet 22 or the second pallet 23 to an individual driving mode to first and second pallet conveying mechanisms 24, 25 for simultaneously conveying the first and second pallets 22, 23.