GAS SUPPLY SYSTEM

A gas supply system includes: a gas tank equipped with a self-closing valve; a gas supply pipe that connects the gas tank to a gas utilization device; and a sealing member. As the gas tank approaches the gas supply pipe, the self-closing valve opens. When a threshold amount of gas fails to be removed from the gas supply pipe within a threshold time after the self-closing valve is closed, the controller outputs a gas removal failure signal. When the threshold amount of gas is successfully removed within the threshold time, the controller calculates an estimate of the pressure in the gas supply pipe after the gas removal. When a measured value from a pressure sensor after the removal of the threshold amount of gas is higher than the estimated value, the controller outputs a valve abnormality signal indicating an abnormality in the self-closing valve.