An internal combustion engine, in which multiple kinds of fuels are fed to a cylinder from multiple fuel injectors each corresponding to each of multiple kinds of fuels at a target mixing ratio determined according to a running condition, includes an actual fuel mixing ratio calculator calculating an actual fuel mixing ratio of fuel fed to cylinder. The actual fuel mixing ratio calculator at first calculates actual fuel injection quantity of each fuel injection by adding or subtracting predetermined stuck-on-wall fuel to or from each quantity of fuel injected from each fuel injector, and then calculates an actual fuel mixing ratio of fuel fed to cylinder on the basis of the calculated actual fuel injection quantity of each fuel injector.