There is provided a mechanochemical sensor including a minute mechanical structure body having the functional membrane formed at least on one part of its surface, a supporting part for supporting the minute mechanical structure body; and a detection part for detecting the change of a mechanical property of the minute mechanical structure body. According to the invention, it is possible to provide improved adhesion between the functional membrane and the minute mechanical structure body since the functional membrane is integrally formed in advance on the minute mechanical structure body, which will contribute to the increase of detection signal, and improvement of measurement precision and sensitivity.