PURPOSE: To easily and surely form a profile of an intended section in an intended quadratic surface of revolution.

CONSTITUTION: A bar shaped body 20 the free end section of which is formed into a cutting surface shape is rotated or rocked as a cutting tool around a rotating shaft 30 wherein the aforesaid body is formed in a cylindrical shape, and is provided in such a way that it can be rotated or rocked around the specified rotating shaft 30 with a specified angle maintained with respect to the specified rotating shaft 30, and an intended revolution quadratic surface 10 can be obtained as the machined profile shape of a fire resistant brick 100 by cutting the soft fire resistant brick 100 by a cutting edge formed out of a section formed in a cutting surface shape.