A starter for an internal combustion engine is provided for improving the startability and reducing noise associated with starting. The starter for an internal combustion engine comprises an electric motor, an oil pump driven by the electric motor, an accumulator for accumulating an oil pressure pumped by the oil pump, a hydraulic actuator driven by the oil pressure accumulated in the accumulator, an oil pressure supply control valve for controlling the oil pressure supplied from the accumulator to the hydraulic actuator, a driven gear for rotation integral with a crank shaft of the internal combustion engine, a driving gear connected to the hydraulic actuator, and brought into mesh with the driven gear and driven by the hydraulic actuator when the internal combustion engine is started, an oil pressure sensor for detecting the oil pressure in the accumulator, and an ECU for controlling the electric motor based on the value of the oil pressure in the accumulator detected by the oil pressure sensor. The starter maintains the hydraulic actuator in a usable state irrespective of an operating condition of the engine to reduce a starting time, thereby making it possible to improve the startability and reduce the noise.