Provided is a configuration which prevents an engine from being unable to start in the state in which dew condensation occurred in a fuel injection pump and froze. The present invention relates to a fuel injection pump which is provided with a pump body and a hydraulic head and driven by an engine, and is characterized in that while the engine is in operation, the temperature of the hydraulic head is increased to a dew-point temperature or higher. Consequently, it is possible to increase the temperature of the hydraulic head and remove water in the fuel injection pump while the engine is in operation. Accordingly, the engine can be prevented from being unable to start in the state that dew condensation occurred in the fuel injection pump and froze.