CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

An ECU 1A is provided in an internal combustion engine 50 which uses multiple gaseous fuels as fuel and which is provided with a regulator 60A capable of adjusting pressure of the fuel to be injected in a fuel supply path FR. The ECU 1A performs combustion control of the internal combustion engine 50 on the basis of the amount of heat variation of the fuel when the pressure of the fuel is adjusted by the regulator 60A. The ECU 1A estimates a mixture ratio of the fuel to be used on the basis of the amount of heat variation of the fuel in adjusting the pressure thereof, and performs the combustion control of the internal combustion engine 50 on the basis of the estimated mixture ratio of the fuel to be used. Therefore, the combustion control of the internal combustion engine 50 is performed on the basis of the amount of heat variation of the fuel in adjusting the pressure thereof.