It is an object of the invention to provide a polishing pad capable of high precision optical detection of an endpoint during polishing in progress and prevention of slurry leakage from between a polishing region and a light-transmitting region during the use thereof even after the polishing pad has been used for a long period. It is a second object of the invention to provide a polishing pad capable of suppression of deterioration of polishing characteristics (such as in-plane uniformity) and generation of scratches due to a difference in behavior of a polishing region and a light-transmitting region during polishing. It is a third object of the invention to provide a polishing pad having a polishing region and a light-transmitting region with a concentration of a specific metal equal to or lower than a specific value (threshold value).