Abstract: A plastic cap having a peripheral band 4 which is provided at the lower end of the skirt-like side wall portion of the cap body, wherein the lower end of the skirt-like side wall portion outwardly protrudes, the peripheral band 4 downwardly extends from the protruded portion 10 at the lower end via a breaking line 11 that is circumferentially formed leaving a plurality of bridges 12, a downwardly extending stopper piece 20 is disposed on the side of closing the cap with respect to at least one of the bridges 12, the stopper piece 20 comes into contact with the bridge 12 at the time of closing the cap, and the cap body and the peripheral band 4 turn together. There is no need of providing space for forming stoppers between the lower end of the skirt-like side wall and the upper end of the peripheral band portion. Therefore, the coupling portion between the two is easily formed by providing a breaking line in the subsequent working of cutting.