The fuel cap includes an outer cap as an outer envelope. The fuel cap includes an inner cap removably fitted in the outer cap through an opening of the outer cap. The fuel cap includes a canister located in a space between the outer cap and the inner cap for adsorbing a vaporized fuel. The fuel cap closes a fuel filler port for feeding a fuel to a fuel tank. The canister adsorbs a vaporized fuel vaporized from the fuel in the fuel tank. At least one of the outer cap and the inner cap defines a communication hole communicating with the space and an exterior. The canister includes a housing; and an adsorbent accommodated in the housing. The housing defines, on an end surface directed to the inner cap, an inlet for a vaporized fuel to flow into the inlet. The housing defines, on another end surface directed to the outer cap, an outlet for a gas, from which the vaporized fuel has been absorbed, to flow out of the outlet. An inner surface of the outer cap and said another end surface of the inner cap having a clearance securement member interposed therebetween and located proximate to the outlet, the spacer securing a clearance between the inner surface of the outer cap and said another end surface of the inner cap.