This paper introduces a Photoacoustic Spectroscopy (PAS) sensor using a highly sensitive pressure sensor composed of silicon piezoresistive cantilever for continuous non-invasive measurement of blood glucose. By measuring photoacoustic waves generated by far-infrared light with the silicon piezoresistive cantilever, the sensor can measure the photoacoustic waves without resonator. This enables to miniaturize the sensor size. The minimum resolution of the silicon piezoresistive cantilever was about 10 µPa, and we confirmed that the prototype PAS sensor can be used to measure 60 mg/dL density glucose in liquid.