This study presents a pressure sensor that can measure the pressure inside the human body. In the medical field, many pressure sensors have been developed for therapeutic applications. However, these pressure sensors require the whole sensor body to be put into the inside of the patient via surgical operations so that the measurement physically burdens patients. Here, we propose a needle-type pressure sensor with a built-in piezoresistive cantilever. The proposed sensor has a needle part with a thin membrane on the tip and is filled with incompressible liquid inside. By ply inserting a needle part into a target, we can measure the body fluid pressure with minimal invasiveness. The resistance of the built-in piezoresistive cantilever varies according to the pressure change applied to the needle tip. Because the fabricated sensor responded to pseudo body pressure, it was suggested that the fabricated needle-type pressure sensor could detect pressure change inside the body.