A surface stress sensor (1, 101, 201, 301, 501) comprising: a membrane (22, 122, 122a, 122b, 122c, 322) configured to be bent by applied surface stress; a frame member (24, 124, 124a, 124b, 124c) configured to be separated from the membrane (22, 122, 122a, 122b, 122c, 322) and surround the membrane (22, 122, 122a, 122b, 122c, 322) when viewed from a thickness direction of the membrane (22, 122, 122a, 122b, 122c, 322); at least a pair of coupling portions arranged at positions sandwiching the membrane (22, 122, 122a, 122b, 122c, 322) when viewed from the thickness direction and configured to couple the membrane (22, 122, 122a, 122b, 122c, 322) and the frame member (24, 124, 124a, 124b, 124c); a flexible resistor configured to be disposed on at least one of the coupling portions and have a resistance value changing according to bending induced in the coupling portion; and a support base member configured to be connected to the frame member, wherein a cavity portion is disposed between the membrane and the support base member, and between the coupling portions and the support base member, characterized in that the support base member overlaps the membrane (22, 122, 122a, 122b, 122c, 322) and the coupling portions when viewed from the thickness direction, further comprising a package substrate connected to a face of the support base member on an opposite side to a face of the support base member facing the membrane (22, 122, 122a, 122b, 122c, 322), wherein the support base member and the package substrate are connected to each other by a connecting portion arranged at a position at which the connecting portion overlaps at least a portion of the membrane (22, 122, 122a, 122b, 122c, 322) when viewed from the thickness direction, and when viewed from the thickness direction of the membrane (22, 122, 122a, 122b, 122c, 322), an area of the connecting portion is smaller than an area of the membrane (22, 122, 122a, 122b, 122c, 322). a membrane (22, 122, 122a, 122b, 122c, 322) configured to be bent by applied surface stress; a frame member (24, 124, 124a, 124b, 124c) configured to be separated from the membrane (22, 122, 122a, 122b, 122c, 322) and surround the membrane (22, 122, 122a, 122b, 122c, 322) when viewed from a thickness direction of the membrane (22, 122, 122a, 122b, 122c, 322); at least a pair of coupling portions arranged at positions sandwiching the membrane (22, 122, 122a, 122b, 122c, 322) when viewed from the thickness direction and configured to couple the membrane (22, 122, 122a, 122b, 122c, 322) and the frame member (24, 124, 124a, 124b, 124c); a flexible resistor configured to be disposed on at least one of the coupling portions and have a resistance value changing according to bending induced in the coupling portion; and a support base member configured to be connected to the frame member, wherein a cavity portion is disposed between the membrane and the support base member, and between the coupling portions and the support base member, characterized in that the support base member overlaps the membrane (22, 122, 122a, 122b, 122c, 322) and the coupling portions when viewed from the thickness direction, further comprising a package substrate connected to a face of the support base member on an opposite side to a face of the support base member facing the membrane (22, 122, 122a, 122b, 122c, 322), wherein the support base member and the package substrate are connected to each other by a connecting portion arranged at a position at which the connecting portion overlaps at least a portion of the membrane (22, 122, 122a, 122b, 122c, 322) when viewed from the thickness direction, and when viewed from the thickness direction of the membrane (22, 122, 122a, 122b, 122c, 322), an area of the connecting portion is smaller than an area of the membrane (22, 122, 122a, 122b, 122c, 322). characterized in that the support base member overlaps the membrane (22, 122, 122a, 122b, 122c, 322) and the coupling portions when viewed from the thickness direction, further comprising a package substrate connected to a face of the support base member on an opposite side to a face of the support base member facing the membrane (22, 122, 122a, 122b, 122c, 322), wherein the support base member and the package substrate are connected to each other by a connecting portion arranged at a position at which the connecting portion overlaps at least a portion of the membrane (22, 122, 122a, 122b, 122c, 322) when viewed from the thickness direction, and when viewed from the thickness direction of the membrane (22, 122, 122a, 122b, 122c, 322), an area of the connecting portion is smaller than an area of the membrane (22, 122, 122a, 122b, 122c, 322).