Patent ID: 7377178

Claim:
A strain detector comprising: an insulating substrate having at least two strain resistance elements and a circuit electrically connected to the strain resistance elements; and a pair of holding members for holding the insulating substrate, the insulating substrate being sandwiched between the holding members, wherein the insulating substrate includes a detection hole provided nearly at the center of the insulating substrate, and a fixing hole provided at a peripheral end zone of the insulating substrate; a portion around the detection hole is pressed by a pressing member; each of the holding members is provided with a fixing hole arranged so as to oppose the fixing hole of the insulating substrate; and a fixing member is inserted into the fixing holes of the holding members and the fixing hole of the insulating substrate so as to secure the peripheral end zone of the insulating substrate, wherein the portion around the detection hole in the insulating substrate is flexible in a vertical direction with respect to the pair of holding members, and wherein the portion around the detection hole in the insulating substrate faces the holding members across a gap.