The invention provides a quarter wave plate, optical pickup device and reflective liquid crystal display device capable of enabling the optical characteristic of ellipticity to be close to 1, and the quarter wave plate is formed by crystal plates of special cutting angle, the optical axis position angle theta of the crystal plate is determined according to the prescribed relational expression in a range of the cutting angle 15 DEG<=theta<=45 DEG. The design phase difference gamma is determined according to the prescribed relational expression corresponding to the cutting angle. The determinedoptical axis position angle theta and the design phase difference gamma are combined, thereby correcting the variation part of the polarization state based on the crystal optical rotation and enabling the ellipticity to be set to the best value close to 1.