A syringe cap is configured to be removably attached to a barrel to seal a needle hole in a puncture needle held by a barrel tip portion of the barrel, and comprises a first member that is configured to be pierced with the puncture needle and that comprises an elastic material having a Young's modulus in the range of 1 to 10 MPa； and a second member that comprises an elastic hollow body having a Young's modulus in the range of 1 to 10 MPa and that is configured form a closed space between the first member and the barrel. A vapor permeability of a material from which the first member is formed is lower than a vapor permeability of a material from which the second member is formed.
