Ignition control device for internal combustion engine

An ignition control device for an internal combustion engine having a single cylinder and a crankshaft, comprising:

• a rotor rotatable in synchronism with the crankshaft of the internal combustion engine and provided on its outer circumference with a plurality of position detecting portions;
• position detecting means for detecting the plurality of position detecting portions sequentially in accordance with the rotation of the rotor;
• and
• ignition control means for controlling an ignition timing of the internal combustion engine on the basis of a detection result of the position detecting means,
• wherein the position detecting portions includes a pair of first position detecting portions arranged at a spacing of a predetermined angle in forward and backward rotating directions across an angular position of a top dead center positioned between a compression stroke and an explosion stroke of the cylinder, and a pair of second position detecting portions arranged at a spacing of a predetermined angle in the forward and backward directions across angular positions of two portions of a circumference of about one divided by an integer number (1/N) in the forward and backward rotating directions with respect to the angular position of the top dead center, such that only the length of one of the first position detecting portions of the first position detecting portions and the second position detecting portions is different.