A movable device (11) of acceleration sensors (11, 21) and a vibration device (12) of a gyroscope (12, 22) are formed on the same sensor wafer (10) spaced apart from each other by a wall (16). A cap wafer (20) having gaps (21, 22) corresponding to the movable mechanical components (11, 12) of the acceleration sensors and gyroscope is provided for the wafer (10) and an adsorbent (24) divided into a plurality of divisional portions is disposed in the gap (22) for the gyroscope (12, 22). After the sensor wafer (10) and the cap wafer (20) have been bonded together at a temperature of inactivation of the adsorbent (24) and in an atmospheric pressure ambience of noble gas and activated gas, the adsorbent divisional portions are activated in sequence to adsorb the activated gas so as to adjust the pressure inside the gyroscope (12, 22), thus manufacturing a combined sensor wafer (10, 20).