A pressure sensor comprising: a pressure detection element; a base in which said pressure detection element is fixed to an inner surface; a receiving member which is arranged so as to face to said base; a diaphragm which is pinched by said base and said receiving member; a pinching member which pinches said base and said receiving member in a state of pinching said diaphragm in such a manner as to prevent both of said base and said receiving member from moving away from each other, the pinching member being installed from any one side of said base and said receiving member, and being bonded by welding to any other side of said base and said receiving member; and a liquid which is sealed in a pressure receiving space between said base and said diaphragm, wherein a pressure in a pressurizing space between said receiving member and said diaphragm is transmitted to said pressure detection element via said diaphragm and said liquid, characterized in that the pinching member comprises: a cylinder portion having an inner diameter which is somewhat larger than an outer diameter of the base and the receiving member in a state of pinching the diaphragm, an outer peripheral portion having a plane which is vertical to a center axis of the pinching member, and an inclined portion which is formed continuously in the upper portion of the cylinder portion via the outer peripheral portion, and is provided so as to be inclined in a direction of a center axis of the cylinder portion, wherein a gap is formed between said pinching member and one of said base and said receiving member, and wherein the welding is done in a state in which a load is applied in a direction in which both of the base and the receiving member are pressed towards each other so as to compress the air gap. a pressure detection element; a base in which said pressure detection element is fixed to an inner surface; a receiving member which is arranged so as to face to said base; a diaphragm which is pinched by said base and said receiving member; a pinching member which pinches said base and said receiving member in a state of pinching said diaphragm in such a manner as to prevent both of said base and said receiving member from moving away from each other, the pinching member being installed from any one side of said base and said receiving member, and being bonded by welding to any other side of said base and said receiving member; and a liquid which is sealed in a pressure receiving space between said base and said diaphragm, wherein a pressure in a pressurizing space between said receiving member and said diaphragm is transmitted to said pressure detection element via said diaphragm and said liquid, characterized in that the pinching member comprises: a cylinder portion having an inner diameter which is somewhat larger than an outer diameter of the base and the receiving member in a state of pinching the diaphragm, an outer peripheral portion having a plane which is vertical to a center axis of the pinching member, and an inclined portion which is formed continuously in the upper portion of the cylinder portion via the outer peripheral portion, and is provided so as to be inclined in a direction of a center axis of the cylinder portion, wherein a gap is formed between said pinching member and one of said base and said receiving member, and wherein the welding is done in a state in which a load is applied in a direction in which both of the base and the receiving member are pressed towards each other so as to compress the air gap. a cylinder portion having an inner diameter which is somewhat larger than an outer diameter of the base and the receiving member in a state of pinching the diaphragm, an outer peripheral portion having a plane which is vertical to a center axis of the pinching member, and an inclined portion which is formed continuously in the upper portion of the cylinder portion via the outer peripheral portion, and is provided so as to be inclined in a direction of a center axis of the cylinder portion, wherein a gap is formed between said pinching member and one of said base and said receiving member, and wherein the welding is done in a state in which a load is applied in a direction in which both of the base and the receiving member are pressed towards each other so as to compress the air gap.