The present invention provides a small-size light-weight electric motor integrated hydraulic motor which is simple in configuration, integrally includes an electric motor and a hydraulic motor, and is capable of efficiently operating, by being configured such that: a swash plate type hydraulic motor and an electric motor driven by the swash plate type hydraulic motor are provided in one casing; the casing is filled with oil; a driving shaft of the swash plate type hydraulic motor is configured to extend from a front end portion of the casing up to a rear end portion thereof and be supported at the front and rear end portions of the casing; the swash plate type hydraulic motor and a rotor of the electric motor are provided in series at the driving shaft; and a stator of the electric motor is fixed to an inner side portion of the casing.