A pressure sensor includes a gold-silicon eutectic crystal layer interposed between the contact layer and the silicon substrate. Because the contact layer and the silicon substrate are electrically connected to each other by using a gold-silicon eutectic reaction at the time of bonding the silicon substrate and the glass substrate, a contact resistance between the contact layer and the silicon substrate can be stabilized, and a Q value of the sensor can be stabilized. In addition, since the contact layer and the silicon substrate are bonded to each other by the gold-silicon eutectic reaction, the bonding strength is sufficient.