COMBUSTION DEVICE

The combustion device includes: a burner; an igniter; a fuel supply unit that supplies fuel to the burner; a blower fan that supplies air for combustion; an exhaust port that discharges combustion exhaust; a device control unit that, before ignition of fuel supplied to the burner by operation of the igniter, performs air purge of the burner at a predetermined air blowing amount by driving the blower fan; and a setting means that is set when a check valve for preventing back flow of exhaust is connected to the exhaust port. When the setting means is set to indicate that the check valve is connected, the device control unit controls the operation of the blower fan so that slow-start air purge is performed in which the time interval from the start of air purge until the predetermined air blowing amount is reached becomes longer, than in the case in which no such check valve is connected.