PURPOSE: To prevent occurrence of engine trouble and to lower the cost of an igniting apparatus for a rotary engine, by using a diode distributor type ignition coil on the trailing side of the igniting apparatus and using the diode distributor type or a simultaneous ignition type ignitioncoil on the leading side of the igniting apparatus.

CONSTITUTION: In the drawing, a rotor 11 of a rotary engine is in the state of starting explosion, that is, in the state of causing ignition, while a rotor 12 is in the state of starting exhaust or compression stroke. At the time of igniting plugs 7, 9 of the rotor 11, main spark is emitted to the plugs 7, 9 and ineffective spark is emitted to a plug 8. However, since a diode distributor type ignition coil 2 is used in this engine, ineffective spark is not emitted to a plug 10. Further, since combustion gas is charged in a rotor space 12a and unburnt gas is charged in a rotor space 12b, emission of spark to the plug 8 does not cause any trouble. However, if spark is emitted to the plug 10, unburnt gas is ignited, so that engine trouble is caused. On the other hand, an igniting apparatus using a diode distributor type ignition coil which does not cause ineffective emission of sparks is used on the trailing side, so that engine trouble is not caused.