GAS CIRCUIT BREAKER

An object of the present invention is to promote the optimization of a usage time limitation function of performing a suitable registration of an appliance flow rate. There are included a flow rate detection unit 10 that measures a flow rate; an average flow rate calculation unit 12 that obtains an average flow rate from instant flow rates which are obtained by calculating instant flow rate values from a detection value by a flow rate calculation unit 11; a flow rate change decision unit 13 that decides whether or not an appliance change flow rate appears based on the obtained average flow rate; an increase flow rate registration unit 14a that registers the flow rate change at the time of increase change decision; a decrease flow rate registration unit 14b that reduces and corrects the registered flow rate near the flow rate change at the time of decrease change decision; a registered flow rate summarization unit 15 that obtains a registered flow rate total value; a flow rate difference decision unit 16 that calculates a flow rate difference from the average flow rate and the registration total flow rate to re-register the flow rate difference or reduce and correct the flow rate difference in the flow rate registration unit; and a cutoff unit 19 that cuts off the supply of gas when an abnormality is decided from the registered flow rate and the monitoring decision value by an abnormality decision unit 17.