Pressure sensor

A pressure sensor comprising:

• a pressure receiving diaphragm that receives pressure;
• a sensing unit that outputs a signal according to a level of pressure;
• a pressure transmitting rod that transmits the pressure received by the pressure receiving diaphragm to the sensing unit;
• and
• a case that houses the sensing unit and the pressure transmitting rod, wherein,
• the pressure transmitting rod is arranged inside the case such that a first end thereof sits on a sensing unit side and a second end thereof sits on a pressure receiving diaphragm side,
• the case has a sensing unit housing portion that houses the sensing unit and a pipe portion that extends from the sensing unit housing portion in a form of a pipe,
• the pipe portion has a first end located adjacent to the sensing unit housing portion and a second end located away from the sensing unit housing portion,
• the second end of the pipe portion has an opening,
• the pipe portion is constructed of an inner pipe and an outer pipe,
• the inner pipe is arranged inside the outer pipe and fixed to the outer pipe, and
• the pressure receiving diaphragm is welded to the inner pipe at the second end of the pipe portion such that the pressure receiving diaphragm covers an opening of the inner pipe.