PURPOSE: To improve the starting performance of an engine by discriminating a cylinder to be ignited on the basis of the combustion chamber pressure in each cylinder and executing the ignition control for the cylinder.

CONSTITUTION: A pressure sensor 11 is installed into a spark plug 4 in each cylinder and inputs the pressure signal of a combustion chamber into a controller 12. When a starter switch is turned-ON, a pressure judging part 12a judges the presence of the input of each cylinder signal which displays a prescribed ignition standard cylinder and the presence of the input of the TOP signal, and if the TOP signal is present, the posterior period of the compression cycle in a certain cylinder is judged. When an ignition cylinder judging part 12b judges that the first cylinder is in the posterior period of the compression cycle and is the cylinder to be ignited, an ignition control part 12e ignites the first cylinder through a transistor circuit 5 and an ignition coil 6. In the successive execution of the similar judgement of each cylinder, the cylinder to be ignited is judged by the combustion chamber pressure in each cylinder even if each cylinder signal is not inputted immediately after the start of cranking, and the ignition control for the cylinder is carried out, and the engine start performance can be improved.