To provide an ignition method of a wood pellet fuel combustion system capable of safe ignition by suppressing generation of uncombusted gas even in the case of using solid fuel such as wood pellet fuel.

After preheating a burner 17 by activating an ignition heater 18, a small amount of pellet 3 for ignition is supplied to the burner 17. Further, a certain amount of air is supplied to the burner 17 with an air supply and discharge blower, and the supplied pellet 3 is ignited by the heating of the ignition heater 18. After that, the supply amount of the pellet 3 into the burner 17 is increased in stages, and the supply amount of air into the burner 17 from the air supply and discharge blower is also increased, thereby suppressing the generation of uncombusted gas at the time of ignition so as to ignite the pellet 3 safely.