PURPOSE: To miniaturize a sensor, by eliminating a column portion from a sensor section to make it thinner.

CONSTITUTION: A sensor body 16 has a shaft section 17 at the center thereof to receive an external force and three elastic beams 18 are extended outward radially from the bearing section 17 with the tip of the respective elastic beams 18 linked to a ring-shaped linking section 19. The sensor body 16 has the center of the link section 16 aligning the center of the shaft section 17 and the angle between the adjacent elastic beams 18 are set at 120° to make them symmetrical as a whole. The sensor body 16 having sets of strain gauges 20-1W20-4, 21-1W21-4 and 22-1W22-4 mounted thereon, four per set are housed in housings 23 and 24. Thus, the sensor section 5 is made so thinner as to permit a smaller size and a lighter weight.