PURPOSE: To accurately incline and grip an object to be gripped by a simple device by arranging an inclination positioning surface on a base so that a rotational position can be adjusted with the center perpendicular to a base gripping surface as the axis in a base device to grip the object to be gripped in an inclined condition.

CONSTITUTION: When inclining work is performed on a work, first of all, a central pin shaft 8 fixed to an inclination positioning piece 7 is inserted in a through-hole of a base 5. Next, this inclination positioning piece 7 is rotated so that a desired inclination is applied to a reference surface 1a of a vise body 1. Next, a positioning pin 9 is pushed in the inclination positioning piece 7 so as to be inserted in selected one among positioning holes 5b..., and a work gripping surface 5a of the base 5 and the inclination positioning piece 7 are connected to each other. Afterwards, one surface of the work is placed on an upper side inclination positioning surface 7a of the inclination positioning piece 7, and an upper surface of the work is worked in parallel to the reference surface 1a.