To restrict a gas leak amount with simple constitution in the case of the breakage of a sensor chip.

A case 14 consists of a case main part 14a having a storage recessed part 14c where the sensor chip 13 is mounted and a projection tube part 14b having a pressure intake passage 19. At a halfway part of the pressure intake passage 19, a gas leak restriction part 19a which has a small diameter (≤0.5 mmμ) is provided so as to restrict the amount of a gas leak to the outside in the case of the breakage of the sensor chip 13. The pressure intake passage 19 is formed of an insert pipe 23. A lid 15 put covering the case 14 is provided integrally with a fitting plate part 20 for screwing to a fitting part 12. An engagement hole 24 is bored in the lid 15 and an elastic engagement claw 25 is provided to the case 14; and they are engaged with each other to couple the lid 15 and case 14 with each other so that they can slightly shift and move.