ROTATION TOOL

Provided is a rotation tool such that thermal shock resistance is high, that the amount of cermet sintered body deformation resulting from burning can be made small, and that machining dimensional accuracy is high. The aforementioned rotation tool is formed of cermet (1) which consists of a hard phase (2) and a bonded phase (3), the aforementioned hard phase (2) being composed of a first hard phase (2a) having a high Ti content ratio and of a second hard phase (2b) having high content ratios of those metals in the fourth, fifth and sixth groups of the periodic table which are other than Ti. When X-ray diffraction measurement is made on the surface of the cermet (1), detection is made of two peaks which belong to a surface (220) of the hard phase (2). An intensity ratio Ib/Ia is a peak detected on a high angle side. Furthermore, a surface region (4) consisting mainly of the first phase exists with a thickness of 1 - 10 µ on the surface of the cermet (1); or a ratio ws/wi is equal to 1.1 - 1.7, where ws is the half-value width of a peak which belongs to a surface (200) of the bonded phase (3) on the surface of the cermet (1), and wi is the half-value width of a peak of the bonded phase inside the surface of the cermet (1).