A gauge (10) for a three-dimensional coordinate measurer fixed onto the measurement table of the three-dimensional coordinate measurer to measure by utilizing the center-to-center distances of spheres and the axis and plane formed of the centers of the plurality of spheres, wherein fitting grooves (2) are formed in the surface of a cylindrical or conical holding body (1) and spherical fixing members (4) having the plurality of spheres (3) arranged thereon are fixedly fitted to the fitting grooves (2), and a standard ring gauge (5) is formed in the holding body (1), whereby three items, that are, scale calibration, straightness, and squareness of the three-dimensional coordinate measurer can be evaluated simultaneously merely by one measurement.