To provide a self combustion agent heater which is securely ignited even when an abrupt operation is performed without absorbing humidity by a heating agent, without a danger of any secondary accident happening.

The present self combustion agent heater is adapted such that an electric ignition tool 2 is inserted into a closed container 10 in which a solid self combustion agent 1 is accommodated, in close vicinity of the self combustion agent 1 and a degassing section 4 in the close container 10, separated from the self combustion agent 1 through a filter 3. Hereby, the degassing section 4 is opened from a closed state with the aid of combustion heat or combustion expansion pressure of the self combustion agent 1.