Abstract: Disclosed is a blood pressure measuring unit comprising a casing having a wrist band to be wound around a user's wrist. The casing is installed therein with a digital display device and a blood pressure measuring device, and is provided with an air pressure chamber to which cuffs are fixed in such a manner that the cuffs are communicated with the air pressure chamber. The blood pressure measuring device is composed of a pressure sensor having a pressure sensing portion, an oscillating circuit, and a processor, the pressure sensing portion being slightly allowed to project into the air pressure chamber, and the processor being electrically connected to the digital display device.