A fiber Bragg grating stuck onto the juncture between two dual-isosceles triangle cantilever beams along the beam axis, which overlaps each other, is employed to act as a force sensor. It is demonstrated in theory and experiment that this passive device can automatically perform compensation for Bragg wavelength shift induced by temperature. Experimental results show that a sensitivity of 6.2 nm/N has been achieved within the working range of 0～0.34 N.