To readily and accurately mount a pressure sensor 31 to a back cover 11 in a timepiece equipped with a diver's watch or an altimeter.

The pressure sensor 31 in the timepiece is provided in an intermediate ring 33 for forming one portion of a sensor module 30, and further comprises an additional printed circuit board (PCB) 34, a sensor support section 35, and a contact element 38. The contact element 38 is arranged between the additional PCB 34 and a main PCB. For achieving accurate arrangement to a back cover 11, the intermediate ring 33 has a sensor support section 35, engaged with a hole formed on the additional PCB 34 and the sensor support section 35. An O-ring sealing joint 32 is compressed in the radial direction, between the wall of an orifice 12 of the back cover 11 and a stiff tubular case 47 in the pressure sensor 31. The back cover 11 is covered with a porous cover from the outside.