ENGINE RESTART DEVICE

To stop an engine at a position before a compression top dead center regardless of fluctuation of an atmospheric pressure when reversely rotating a crankshaft after stopping the engine to prepare for the next start. [0002] A controller (160) performs idle stop when the stop of the vehicle is detected based on the vehicle speed, and performs idle stop control to normally rotate the crankshaft after reversely rotating it when restarting the engine. The controller (160) controls the speed at which the crankshaft (12) is reversely rotated by a starter/generator (171) in accordance with the measurement result of the atmospheric pressure by an atmospheric pressure measuring unit (252). The atmospheric pressure can also be measured with reference to the detected value of an intake pressure sensor of the engine. The controller (160) changes a drive duty ratio of the starter based on the measurement result of the atmospheric pressure. The correspondence relationship between the atmospheric pressure and the drive duty ratio is stored in a map format (307), and the controller (160) refers to the map based on the measurement result of the atmospheric pressure to determine the drive duty ratio.