A control device is provided which prevents a temperature increase within an ECU by suppressing heat generation in the ECU without using a new cooling device such as a blow fan. In one step, an open valve voltage target value is calculated. An open valve voltage is a voltage applied to a fuel injection valve when opening the fuel injection valve. As the number of times of the multi-stage injections increases, an opportunity to boost the open valve voltage increases, heat is generated in the open valve voltage boosting section, a temperature within the ECU excessively increases, and there is a concern that an electronic component within the ECU malfunctions or fails. Thus, a temperature sensor is provided on an inside of the ECU and if an ECU temperature is high, it is determined that heat is generated in the open valve voltage generating section and the open valve voltage target value is reduced.