PURPOSE: To provide a sealing zip which can seal and unseal a bag as easily as the conventional one and can impart an extremely high sealing strength to the bag.

CONSTITUTION: In a sealing zip consisting of a depressed internal part 1 and a raised external part 2 which is press fitted into the depressed internal part 1, when at least the inner bottom surface of the depressed internal part 1 is located in a low position and the inserting raised part of the raised external part 2 is located in a higher position, three small raised locking tracks 3 are provided lengthwise of the depressed internal part 1, so that they are located at the three places of the depressed internal part, i.e., the left and right sides and the lower part.