A thermal-type air flow meter comprising: a sensor assembly (100, 100 ', 100 '') insert molded using a first resin, which sensor assembly includes a circuit unit having a resistor and a flow rate detection unit which are configured so as to expose at least a part of the flow rate detection unit; and a housing which has a secondary passage and houses the sensor assembly (100, 100', 100'') by allowing the flow rate detection unit to be arranged inside the secondary passage, wherein the housing is molded using a second resin, wherein the sensor assembly (100, 100', 100'') is fixed by insert molding of the housing to the housing via the second resin forming the housing; characterized in that the first resin and the second resin are different materials, and in that the thermal-type air flow meter further comprises a resin structure which is adapted to cause a tensile stress in a direction parallel to a surface on which the flow rate detection unit is exposed with respect to the sensor assembly, wherein the tensile stress causing warping deformation in the sensor assembly, wherein the resistor of the circuit unit is positioned at a part on which the tensile stress acts, wherein the resin structure is constituted by one of the following: a) a volume of the second resin which is in contact with the surface on the rear surface side of the sensor assembly (100, 100', 100'') with respect to the circuit unit is larger than a volume of the second resin which is in contact with the surface on the front surface side of the sensor assembly (100, 100', 100'') with respect to the circuit unit; b) a thickness of the first resin provided on the rear surface side of the sensor assembly (100, 100', 100'') with respect to the circuit unit is set to be thicker than a thickness of the first resin provided on the front surface side of the sensor assembly (100, 100', 100'') with respect to the circuit unit; or a combination of a) and b). a sensor assembly (100, 100 ', 100 '') insert molded using a first resin, which sensor assembly includes a circuit unit having a resistor and a flow rate detection unit which are configured so as to expose at least a part of the flow rate detection unit; and a housing which has a secondary passage and houses the sensor assembly (100, 100', 100'') by allowing the flow rate detection unit to be arranged inside the secondary passage, wherein the housing is molded using a second resin, wherein the sensor assembly (100, 100', 100'') is fixed by insert molding of the housing to the housing via the second resin forming the housing; characterized in that the first resin and the second resin are different materials, and in that the thermal-type air flow meter further comprises a resin structure which is adapted to cause a tensile stress in a direction parallel to a surface on which the flow rate detection unit is exposed with respect to the sensor assembly, wherein the tensile stress causing warping deformation in the sensor assembly, wherein the resistor of the circuit unit is positioned at a part on which the tensile stress acts, wherein the resin structure is constituted by one of the following: a) a volume of the second resin which is in contact with the surface on the rear surface side of the sensor assembly (100, 100', 100'') with respect to the circuit unit is larger than a volume of the second resin which is in contact with the surface on the front surface side of the sensor assembly (100, 100', 100'') with respect to the circuit unit; b) a thickness of the first resin provided on the rear surface side of the sensor assembly (100, 100', 100'') with respect to the circuit unit is set to be thicker than a thickness of the first resin provided on the front surface side of the sensor assembly (100, 100', 100'') with respect to the circuit unit; or a combination of a) and b). a) a volume of the second resin which is in contact with the surface on the rear surface side of the sensor assembly (100, 100', 100'') with respect to the circuit unit is larger than a volume of the second resin which is in contact with the surface on the front surface side of the sensor assembly (100, 100', 100'') with respect to the circuit unit; b) a thickness of the first resin provided on the rear surface side of the sensor assembly (100, 100', 100'') with respect to the circuit unit is set to be thicker than a thickness of the first resin provided on the front surface side of the sensor assembly (100, 100', 100'') with respect to the circuit unit; or a combination of a) and b).