A device for measuring altitude and barometric pressure having a barometric pressure sensor, an amplifying circuit for amplifying the output signal from the pressure sensor, an analog to digital converter for converting the output signal from the amplifying circuit to a digital signal, and an altitude information generator for generating altitude information from the output signal of the analog to digital converter. A display displays the altitude information from the altitude information generator and the pressure information detected by the pressure sensor with pressure variation information and converts it into precise altitude information in accordance with temperature compensation data and altitude compensating data based upon regional and time information. The device may be used in climbing or the like with remarkable reliability.