A reference point on a table center of an inclined rotating table in a wire electric discharge machine is obtained using a measuring jig. A biaxial rotation unit is placed on a table of the wire electric discharge machine. The measuring jig has a shape most suitable for reference point measurement using a contact sensing function of a wire electrode which a wire electric discharge machine generally has and includes a fixed section for being fixed to a work fixing section of the biaxial rotation unit, an arm section which is provided to stand on the fixed section, and a section to be measured which is provided at a distal end of the arm section and has a conductive spherical surface.