PURPOSE: To eliminate the necessity of preparation of a new sheave and to make it possible to carry out working in a short time, by providing a miniature lathe adjustably of its level in the vicinity of the sheave so that grooves in the sheave are cut by a cutting tool to reform the grooves.

CONSTITUTION: In a method of cutting grooves 4a in a sheave 4, a wire rope 7 is removed from the sheave 4, and a miniature lathe 20 is set on a lathe bed 8b whose set level is adjusted simultaneously so that a cutting tool is aligned with the grooves 4a so that the preparation of lathing is completed. The outer periphery of the sheave 4 is cut by a depth corresponding to the amount of abrasion by the outerperiphery cutting tool 30 while a cross-feed handle 25 is manipulated. Then, after exchanging the cutting tool with a thrust cutting tool 31, adjustment is made such that the cutting tool 31 is set at the center of each groove 4a by manipulating cross and transverse feed handles 25, 27. Therefore, cutting is made by the transverse feed handle 25 by a depth equal to the depth cut by the previous cutting tool 30. Thus, the time of working may be made in a short time without replacing the sheave with a new one.