A synthetic-resin container lid for being applied to a container formed with an external thread, and a locking jaw section located below the external thread, on an outer peripheral surface of a mouth-neck portion, the synthetic-resin container lid comprising: a body having a top panel wall, and a cylindrical skirt wall extending downward from a peripheral edge of the top panel wall, an inner peripheral surface of the skirt wall being formed with an internal thread to be screwed to the external thread; and a cylindrical tamper-evident bottom portion which is connected to the skirt wall via a breakable line extending in a circumferential direction, and which has an inner peripheral surface where locking means to be locked to the locking jaw section is disposed, wherein the breakable line is defined by forming a plurality of first scores extending in the circumferential direction at intervals in the circumferential direction, or by forming a groove continuously in the circumferential direction to reduce a residual thickness, except for a specific region extending in the circumferential direction, in the specific region a pair of second scores extending in the circumferential direction at an interval in the circumferential direction in a lower part of the skirt wall; a pair of third scores extending in the circumferential direction at an interval in the circumferential direction in an upper part of the tamper-evident bottom portion; a pair of fourth scores extending in the circumferential direction at an interval in the circumferential direction in the tamper-evident bottom portion axially below the third scores; and a fifth score extending in the circumferential direction in the tamper-evident bottom portion axially below the third scores are formed, wherein the second scores, the third scores, the fourth scores, and the fifth score each extend circumferentially linearly and substantially horizontally, and an inner end of each of the third scores is located circumferentially outside an inner end of each of the second scores; an outer end of each of the third scores is located circumferentially outside an outer end of each of the second scores; an inner end of each of the fourth scores is located circumferentially inside the inner end of each of the third scores; and each of both ends of the fifth score is located in alignment with, or circumferentially outside, the inner end of each of the second scores and the inner end of each of the fourth scores, a pair of sixth scores extending in an axial direction is further formed in the specific region, the sixth scores connecting inner end parts of each of the second scores, connecting inner end parts of the fourth scores, and both end parts of the fifth score, and when each of the third scores is axially offset from the breakable line, seventh scores extending axially, which connect outer end parts of each of the third scores to the breakable line, are further formed in the specific region. a body having a top panel wall, and a cylindrical skirt wall extending downward from a peripheral edge of the top panel wall, an inner peripheral surface of the skirt wall being formed with an internal thread to be screwed to the external thread; and a cylindrical tamper-evident bottom portion which is connected to the skirt wall via a breakable line extending in a circumferential direction, and which has an inner peripheral surface where locking means to be locked to the locking jaw section is disposed, wherein the breakable line is defined by forming a plurality of first scores extending in the circumferential direction at intervals in the circumferential direction, or by forming a groove continuously in the circumferential direction to reduce a residual thickness, except for a specific region extending in the circumferential direction, in the specific region a pair of second scores extending in the circumferential direction at an interval in the circumferential direction in a lower part of the skirt wall; a pair of third scores extending in the circumferential direction at an interval in the circumferential direction in an upper part of the tamper-evident bottom portion; a pair of fourth scores extending in the circumferential direction at an interval in the circumferential direction in the tamper-evident bottom portion axially below the third scores; and a fifth score extending in the circumferential direction in the tamper-evident bottom portion axially below the third scores are formed, wherein the second scores, the third scores, the fourth scores, and the fifth score each extend circumferentially linearly and substantially horizontally, and an inner end of each of the third scores is located circumferentially outside an inner end of each of the second scores; an outer end of each of the third scores is located circumferentially outside an outer end of each of the second scores; an inner end of each of the fourth scores is located circumferentially inside the inner end of each of the third scores; and each of both ends of the fifth score is located in alignment with, or circumferentially outside, the inner end of each of the second scores and the inner end of each of the fourth scores, a pair of sixth scores extending in an axial direction is further formed in the specific region, the sixth scores connecting inner end parts of each of the second scores, connecting inner end parts of the fourth scores, and both end parts of the fifth score, and when each of the third scores is axially offset from the breakable line, seventh scores extending axially, which connect outer end parts of each of the third scores to the breakable line, are further formed in the specific region.