To more suitably determine a condition of retarded control of spark advance enabling an internal combustion engine using a plurality of kinds of fuel to perform retarded control of spark advance.

Respective determination values of an after-start time, an engine water temperature, an intake-air temperature, atmospheric pressure, and an ignition timing are set according to properties of fuel in use. An after-start time determination part 101, an engine water temperature determination part 102, an intake-air temperature determination part 103, an atmospheric pressure determination part 104, and an ignition timing determination part 105 compare an after-start time, an engine water temperature, an intake-air temperature, atmospheric pressure, and an ignition timing which are actually detected with the determination value of fuel identified to be currently in use, and it is determined that the condition of retarded control of spark advance is met as a result of the comparison. A retarded control of spark advance part 108 performs retarded control of spark advance according to the properties of the fuel currently in use when the condition of the retarded control of spark advance is met.