A surface stress sensor comprising: a membrane configured to be bent by applied surface stress; a frame member configured to be separated from the membrane and surround the membrane when viewed from a thickness direction of the membrane ; at least a pair of coupling portions (26, 26a-26d) arranged at positions sandwiching the membrane when viewed from the thickness direction and configured to couple the membrane and the frame member ; a flexible resistor configured to be disposed on at least one of the coupling portions (26, 26a-26d) and have a resistance value changing according to bending induced in the coupling portion (26, 26a-26d);- a support base member configured to be connected to the frame member and overlap the membrane and the coupling portions (26, 26a-26d) when viewed from the thickness direction; a receptor configured to be formed on a region including the center of a front face, the front face being a face of the membrane on an opposite side to a face of the membrane facing the support base member, and be deformed according to an adsorbed substance; wherein a cavity portion is disposed between the membrane and the support base member , and between the coupling portions (26, 26a-26d) and the support base member , characterized by a recess/protrusion pattern configured to be disposed in a region closer to the frame member than a receptor forming region in which the receptor is formed within the front face and have a surface the degree of roughness of which is higher than the receptor forming region, wherein the recess/protrusion pattern is a structure in which a plurality of protruding portions or a plurality of recessed portions are arranged at intervals. a membrane configured to be bent by applied surface stress; a frame member configured to be separated from the membrane and surround the membrane when viewed from a thickness direction of the membrane ; at least a pair of coupling portions (26, 26a-26d) arranged at positions sandwiching the membrane when viewed from the thickness direction and configured to couple the membrane and the frame member ; a flexible resistor configured to be disposed on at least one of the coupling portions (26, 26a-26d) and have a resistance value changing according to bending induced in the coupling portion (26, 26a-26d);- a support base member configured to be connected to the frame member and overlap the membrane and the coupling portions (26, 26a-26d) when viewed from the thickness direction; a receptor configured to be formed on a region including the center of a front face, the front face being a face of the membrane on an opposite side to a face of the membrane facing the support base member, and be deformed according to an adsorbed substance; wherein a cavity portion is disposed between the membrane and the support base member , and between the coupling portions (26, 26a-26d) and the support base member , characterized by a recess/protrusion pattern configured to be disposed in a region closer to the frame member than a receptor forming region in which the receptor is formed within the front face and have a surface the degree of roughness of which is higher than the receptor forming region, wherein the recess/protrusion pattern is a structure in which a plurality of protruding portions or a plurality of recessed portions are arranged at intervals. a recess/protrusion pattern configured to be disposed in a region closer to the frame member than a receptor forming region in which the receptor is formed within the front face and have a surface the degree of roughness of which is higher than the receptor forming region, wherein the recess/protrusion pattern is a structure in which a plurality of protruding portions or a plurality of recessed portions are arranged at intervals. <EOS>