In order to provide means to improve an operating ratio and the like of a fuel cell while keeping using a gas meter and a gas leakage detection system popularly used by a general household, a fuel cell system of the disclosure herein including a fuel cell module configured to generate power by using gas supplied via a gas meter and a controller configured to control the power generation of the fuel cell module, wherein the controller, when detecting for a first predetermined period of time that the gas is not supplied to anything else other than the fuel cell module, controls to stop the power generation of the fuel cell module for a second predetermined period of time.