A pallet positioning and fixing device is provided which has a simple constitution and is capable of positioning a work piece holding pallet to a high degree of accuracy in the horizontal direction and vertical direction, with respect to a base body. In the pallet positioning and fixing device (1), a horizontal receiving face (14) is formed on the upper face of a base body (2), a ring-shaped abutting face (37) which abuts against the receiving face (14) is provided on the lower face of the pallet (3), a clamping mechanism (4) is provided in substantially the central portion of the base body (2) and the pallet (3), a first positioning mechanism (5) capable of positioning the pallet (3) in a horizontal direction and a second positioning mechanism (6) capable of positioning a pallet (3) so as to prevent the same from rotating about a vertical axis are provided on either side of the clamping mechanism (4), the pallet (3) is positioned in the vertical direction by the receiving face (14) and the abutting face (37), and is positioned in the horizontal direction by the positioning mechanism (5, 6), and the pallet (3) is fixed to the base body (2) by the clamping mechanism (4).