An end-point detection sensor 50 detects an end point of polishing, the end-point detection sensor 50 being arranged in a polishing table 100. The end-point detection sensor 50 has a pot core. The pot core 60 has a bottom portion 61a, a magnetic core base portion 61b and a peripheral wall base portion 61c. The end-point detection sensor 50 has an exciting coil 62, and a detection coil 63. The back surface 101b of the polishing pad 101 has a space 30 which is arranged at a portion facing the polishing table 100 and houses a magnetic core extension portion 8 and a peripheral wall extension portion 11. The magnetic core extension portion 8 and the peripheral wall extension portion 11 extending to the space 30 are located in the space 30.