PURPOSE: To obtain safe property and durability, while realizing an engine of large output regardless of its light weight and small size, by utilizing sufficiently strength possessed each part of the internal combustion engine.

CONSTITUTION: A distortion transmitter 6 is installed on a position where maximum stress is supposed to be generated, of any part liable to be broken by an increase in inter-cylinder pressure in an internal combustion engine such as a piston, a connecting rod, a crank shaft, and the like. A signal corresponding to the strain in the position namely the stress is transmitted in the formed of, for example, electric wave, and a signal received by a receiver 11 is inputted in an electronically controlled device 12. And correction is applied to a fuel injection amount and an injection timing, and inter-cylinder pressure is controlled, so that a stress as large as possible may be generated in a safe range.