<p>An elevator modification work apparatus for disposing a coupling shaft mounting aperture on an end surface of a motor shaft includes a positioning member on which a recess portion is disposed into which the motor shaft is fitted. Displacement of the positioning member relative to the motor shaft in a direction that is perpendicular to the axis of the motor shaft is restricted by fitting the end portion of the motor shaft into the recess portion. A motor shaft positioning aperture that passes through the positioning member in a direction that intersects a bottom surface of the recess portion is disposed on the recess portion. A position at which to dispose the coupling shaft mounting aperture on the end surface of the motor shaft is specified by a position of the motor shaft positioning aperture when the end portion of the motor shaft is fitted into the recess portion.</p>