GAS SHUT-OFF DEVICE

An object of the present invention is to perform a suitable registration of a flow rate of appliances to promote the optimization of a usage time limitation function. In a gas shut-off device according to the invention, a flow rate detection unit measures a flow rate, a flow rate calculation unit calculates values of instant flow rates from a detection value, an average flow rate calculation unit obtains an average flow rate from the obtained instant flow rates, a flow rate change decision unit decides the presence or absence of a change in the flow rate based on the obtained average flow rate, a flow rate storage unit stores a value of the obtained average flow rate, an increase flow rate registration unit registers an amount of the flow rate change at the time of increase change decision by the flow rate change decision unit, a decrease flow rate re-registration unit reduces the registered flow rate near an amount of the flow rate change at the time of decrease change decision by the flow rate change decision unit, and re-registers and replaces it with a value of the average flow rate obtained by the average flow rate calculation unit after the reduction of the registered flow rate, and a shut-off unit shuts off the supply of gas when decided as an abnormality by an abnormality decision unit from the registered flow rate and a decision value.