To provide a pressure sensor for paper sheet counter excellent in the measuring performance of vacuum pressure in a hollow shaft through a pressure sensor and the workability of paper sheet counting work.

A paper sheet counter for counting paper sheets while sucking and turning over sheet by sheet comprises a holder for holding the paper sheets to be counted, a tube 3 rotatable about a hollow shaft, a plurality of suction tubes having at least one suction opening communicate with the hollow shaft in one end face of the rotary tube, a suction passage communicating with the hollow shaft and a vacuum pump, and a pressure sensor 8 communicating with the suction passage and detecting pressure variation in the hollow shaft wherein the pressure sensor 8 is fixed to communicate with the suction passage through a thin film 10 of elastic material at the forward end of the pressure introduction pipe 9 of the pressure sensor 8.