An ignition timing control device for an internal combustion engine is capable of preventing shock of an engine upon rapid acceleration by suitably controlling the ignition timing of the engine. When the width of the opening of a throttle valve is kept within a specific width for a first specific time or more in a state where the opening of the throttle valve is smaller than a specific low opening and immediately after, the opening of the throttle valve is increased from the specific low opening to more than a specific high opening for a second specific time or less, it is decided that the internal combustion engine is in a rapid acceleration state. Ignition timing of the engine is therefore retarded.