A device equipped with a tank includes: a tank storing gas; a receptacle to be coupled to a gas supply nozzle; a filling passage communicating the tank with the receptacle; and a determination unit configured to determine whether there is a leak in the filling passage based on an amount of decrease in pressure in the filling passage per unit time, after supplying of the gas cooled to below freezing to the tank through the receptacle and the filling passage is finished, when a temperature of the receptacle is a predetermined temperature or greater and a pressure in the filling passage in a state where all valves opening and closing the filling passage are closed is greater than a first pressure, wherein the receptacle incorporates a check valve inhibiting backflow of the gas from the filling passage.