To easily position a work to a cutting blade in a short time.

A positioning device of a work W1 loaded on a fixed table 1 comprises a shaft member 10 for fixing the work W1 to the fixed table 1, a rotary shaft 20 mounted on a stock vice table 2 for rotating a shaft member 10, and a vice member 30. A shaft 14 of a fixed pad 12 mounted on one end side of the shaft member 10 is provided with a spring member 15. The rotary shaft 20 is provided with an insertion pin 22 fittable into a plurality of pin holes 2a-2f formed on the stock vice table 2. The work W1 is lightly held by an end surface 3a of a fence 3 and an end surface 12a of the fixed pad 12, and the shaft member 10 is rotated on the rotary shaft 20, whereby the work W1 and the fixed pad 12 are integrally moved on the fixed table 1 to align the work W1.