In order to provide a technology capable of suppressing degradation of measurement accuracy due to fluctuation of detection sensitivity of an MEMS by suppressing fluctuation in natural frequency of the MEMS caused by a stress, first, fixed portions 3a to 3d are displaced outward in a y-direction of a semiconductor substrate 2 by deformation of the semiconductor substrate 2. Since a movable body 5 is disposed in a state of floating above the semiconductor substrate 2, it is not affected and displaced by the deformation of the semiconductor substrate 2. Therefore, a tensile stress (+σ1) occurs in the beam 4a and a compressive stress (−σ2) occurs in the beam 4b. At this time, in terms of a spring system made by combining the beam 4a and the beam 4b, increase in spring constant due to the tensile stress acting on the beam 4a and decrease in spring constant due to the compressive stress acting on the beam 4b are offset against each other.