The purpose of the present invention is to provide a synthetic resin cap having good tamper evidence properties while being capable of limiting increases in uncapping torque. Provided is a cap 1 provided with a skirt wall 3 with a female thread 5 that screws together with a male thread formed on the outer circumference of a container mouth section and a tamper evident band 7 connected to the lower part of the skirt wall via a ring-shaped weakened section 6, wherein: multiple hooks 8, which are capable of locking from below with a ring-shaped protrusion 9 provided on the outer circumference of the container mouth section, are provided at intervals in the circumferential direction on the inner circumferential side of the tamper evident band; and on the inner circumferential side of the tamper evident band, protruding parts 10, which protrude to the inside of the tamper evident band, extend above the hooks, contacting parts 11 are provided on the lower part of the protruding parts, and said contacting parts extend so that the internal diameter decreases with a slope θ of at least 20 degrees from the inner circumferential surface of the protruding parts to the upper surfaces of the hooks.