To provide a power source control device of a combustion apparatus for reducing standby electric power consumed during operation halt without complicating the circuit constitution.

This power source control device is provided with an opening- closing detecting means for detecting a first opening-closing state, and a second opening-closing means for controlling electric power supply to a load part and a power transformer. A control part determines operation and halt of the apparatus by a signal of the opening-closing detecting means, and controls the second opening-closing means so as not to supply electric power to the load part and the power transformer after stopping the operation. This first opening-closing means is formed as a unipolar double-throw switch or a means corresponding to this switch, and a circuit is constituted by minimizing the number of base board part items, so that a cost increase and an increase in the base board area are restrained more than a conventional device.