A pressure gauge is composed of two separate components adapted to be assembled and disassembled by hand. The one component is a pressure-motion conversion element (3, 6) for receiving a pressure and effecting a movement of a movable portion (3c, 6c) thereof in response thereto, and the other component is a force measuring element (5) for measuring a force caused due to the movement of the movable portion (3c, 6c). The pressure-motion conversion element (3, 69) is constructed as a disposable component, whereas the force measuring element (5) is intended for re-use.