Even when a strain sensor chip and an object to be measured are bonded to each other by using a metallic bonding material such as solder, the metallic bonding material shows the creep behavior when used under high temperature environment of, for example, 100° C. or higher, and therefore, the strain detected by the strain sensor chip is gradually reduced, and the strain is apparently reduced. In the strain sensor chip mounting structure which is one embodiment of the present application, a strain sensor chip is fixed onto a surface to be measured of the object to be measured via a metallic bonding material. And, the metallic bonding material is bonded to a metallic film that is formed on a side surface of the strain sensor chip. In this manner, temporal change in a measurement error can be suppressed.