An air conditioner (1) comprising at least one compressor (31a, 31b) driven by an engine (40)including at least clutch (38a, 38b) which is coupled to the engine so that the clutch can be connected to and disconnected from the engine, a fuel shut-off valve (95) for interrupting fuel supply to the engine, and a controller (60a) for actuating the clutches to disconnect the compressor from the engine under the state that the compressor is driven by the engine when a signal for instructing stop of the engine is input, and then actuating the fuel shut-off valve to interrupt fuel supply to the engine.