PURPOSE: To simplify the circuit constitution in an internal combustion engine, in which the electrifying time to coils led to cylinders to be ignited in succession can be overlapped, by enabling generation of a basic positional signal of two ignition signals necessary for the overlapping, taking advantage of a cylinder discriminating signal.

CONSTITUTION: A cylinder discriminating signal la, which is outputted syncnronizing with the rotation of a cam shaft, and a crank-basic-position detecting signal lb, which is outputted synchronizing with the rotation of a crank shaft, are inputted into a counter lc. Every time a leading edge of the signal lb is inputted, signals 1 to 3 are inputted, signals 1 to 3 are inputted into an MPU1d as a cylinder discriminating information. In addition, a leading edge and a traiding edge of the least significant bit 1 of binary data are used as a basic positional signal when the ignition signals 4 and 5 for even-numbered and odd-numbered cylinders are generated. The second bit 2 and the third bit 3 from the right of the binary data are used as a channel switching signal of a multiplexer 1f, which is used for distribution of the ignition signal 4 for the odd-numbered cylinders.