A workpiece fixing jig 1 includes a base 2 to be fixed on a table, and a clamping mechanism 10 provided on the base 2 for clamping a workpiece. The clamping mechanism 10 includes a first clamping portion 20 and a second clamping portion 30 provided to face each other. At least one of the first and second clamping portions 20 and 30 is configured to move forward and backward with respect to the other along a moving direction and the moving direction is set to a direction intersecting a direction in which the base 2 is fixed on the table. In using this workpiece fixing jig 1, the base 2 is fixed on the table after the workpiece is clamped between the first clamping portion 20 and the second clamping portion 30.