A pressure sensor comprising: a sensor unit including a housing, a sensor chip configured for detecting a pressure and sending a detection output signal, a chip mounting member supporting the sensor chip, a diaphragm supported by a lower end surface of the housing for partitioning a liquid sealing chamber, in which the sensor chip is placed, from a pressure chamber facing the liquid sealing chamber, and a group of input-output terminals electrically connected to the sensor chip; the housing, a hermetic glass, the chip mounting member, and the diaphragm forming the liquid sealing chamber; and an electric field blocking member electrically connected to one or more of the group of input-output terminals, and for blocking an electric field acting on a signal processing electronic circuit unit of the sensor chip, characterized in that one or more of the group of input-output terminals is electrically connected to the chip mounting member, the electric potentials of the electric field blocking member and the chip mounting member are set to the same electric potential as the electric potential of the electronic circuit mounted in the sensor chip, the chip mounting member has a diameter larger than an external size of the sensor ship, the electric field blocking member is a strip-shaped shielding plate and is placed between one end surface of the sensor chip in the liquid sealing chamber and the diaphragm with a predetermined clearance formed between the one end surface of the sensor chip and a portion of the strip-shaped shielding plate facing the end surface of the sensor chip, and fixing end portions of the strip-shaped shielding plate, which are joined to an end portion of the chip mounting member, are brought close to an outer peripheral portion of the sensor chip at the end portion of the chip mounting member. a sensor unit including a housing, a sensor chip configured for detecting a pressure and sending a detection output signal, a chip mounting member supporting the sensor chip, a diaphragm supported by a lower end surface of the housing for partitioning a liquid sealing chamber, in which the sensor chip is placed, from a pressure chamber facing the liquid sealing chamber, and a group of input-output terminals electrically connected to the sensor chip; the housing, a hermetic glass, the chip mounting member, and the diaphragm forming the liquid sealing chamber; and an electric field blocking member electrically connected to one or more of the group of input-output terminals, and for blocking an electric field acting on a signal processing electronic circuit unit of the sensor chip, characterized in that one or more of the group of input-output terminals is electrically connected to the chip mounting member, the electric potentials of the electric field blocking member and the chip mounting member are set to the same electric potential as the electric potential of the electronic circuit mounted in the sensor chip, the chip mounting member has a diameter larger than an external size of the sensor ship, the electric field blocking member is a strip-shaped shielding plate and is placed between one end surface of the sensor chip in the liquid sealing chamber and the diaphragm with a predetermined clearance formed between the one end surface of the sensor chip and a portion of the strip-shaped shielding plate facing the end surface of the sensor chip, and fixing end portions of the strip-shaped shielding plate, which are joined to an end portion of the chip mounting member, are brought close to an outer peripheral portion of the sensor chip at the end portion of the chip mounting member.