In a fuel vapor release suppression system for a fuel tank, a main tank and a sub tank communicate with each other, and the sub tank and a canister communicate with each other. The control circuit has a sensing circuit, an estimation circuit, an amplifying circuit, a comparing circuit, a zero-cross detection circuit and a logic circuit. In the client 1, a content ID for identifying the content and a unique ID unique to the client 1 are generated, and these IDs are added to the content retrieved by the ripping module 91.