Patent ID: 7992448

Claim:
A mechanical-quantity measuring device provided with a strain detection unit on a surface of a monocrystalline semiconductor substrate, and using a flat back surface of the monocrystalline semiconductor substrate as an adherence surface so as to be attached to a measured object to measure a strain, the device comprising: first and second sensors each having a wheatstone bridge formed by a plurality of diffusion resistors; a first amplifier circuit amplifying a signal outputted by the first sensor; and a second amplifier circuit amplifying a signal outputted by the second sensor; wherein: distances between the plurality of diffusion resistors that form the wheatstone bridge of the first sensor and the plurality of diffusion resistors that form the wheatstone bridge of the second sensor are smaller than a distance between a first transistor of the first amplifier circuit and a second transistor of the second amplifier circuit, longitudinal directions of the plurality of diffusion resistors of the first sensor have a same direction as longitudinal directions of a plurality of feedback resistors configuring the first amplifier circuit, longitudinal directions of the plurality of diffusion resistors of the second sensor have a same direction as longitudinal directions of a plurality of feedback resistors configuring the second amplifier circuit, and the first amplifier circuit of the first sensor and the second amplifier circuit of the second sensor are formed on the monocrystalline semiconductor substrate approximately line-symmetrically with each other.