Patent ID: 7150198

Claim:
A pressure sensor for measuring pressure of a fluid to be measured, comprising: a pressure detector having a bottomed cylindrical member with a bottom formed in a thin-wall portion and a strain gauge formed on the bottom for detecting a strain of the bottom; and a pressure introducing joint for introducing a fluid to be measured inside the bottomed cylindrical member, wherein the bottomed cylindrical member is made of an austenitic precipitation hardening Fe—Ni heat resisting steel containing 24 to 27 wt % of Ni and 13.5 to 16 wt % of Cr, the pressure introducing joint is made of an austenitic stainless steel, an end of a cylindrical portion of the bottomed cylindrical member and an end of the pressure introducing joint are butt-welded to integrate the bottomed cylindrical portion and the pressure introducing joint via a weld portion, and Ni content of the weld portion is adjusted to be higher than an average of Ni content of the bottomed cylindrical member and Ni content of the pressure introducing joint.