In drive control of an operating machine configured to drive a structure by a hydraulic motor configured to be driven by operating oil supplied from a hydraulic pump an electric motor configured to cooperate with the hydraulic motor, a speed command generated based on a manipulation amount of a remote control valve configured to determine an operation amount of the structure is subjected to speed feedback control performed based on the actual rotation speed of the hydraulic motor and pressure difference feedback control performed based on an operating oil pressure difference between a suction port and discharge port of the hydraulic motor. With this, a tilting angle command is generated such that the operating oil, the amount of which is necessary at the actual rotation speed of the hydraulic motor, is ejected, and the tilting angle of the hydraulic pump is controlled.