This paper reports a measurement method of vacuum pressure from 10-1 to 103 Pa with a piezoresistive cantilever-based differential pressure sensor (DPS). The gap around the cantilever of the DPS was narrow (2 μm) so that the air flow through it was suppressed. The through-hole beneath the sensor is connected to a chamber which is filled with saturated vapor. This method allows the pressure of the chamber to be stable at the vapor pressure of the liquid even when the exterior was vacuumed. The exterior vacuum pressure was calculated from the cantilever output since the vapor pressure of the chamber is known. We showed that the lower limit of measurable range was expanded into 0.1 Pa owing to noise reduction. The proposed method is promising to realize wide-range vacuum pressure measurement.