Abstract: To provide a portable biological data measuring apparatus capable of measuring, storing and displaying biological data of a human being, in particular. The apparatus includes a GND electrode (12B) and a minus electrode (12C) which are provided on the opposite side faces of a roughly rectangular parallelopiped-shaped chassis (11), and a plus electrode (12A) provided on the face curved into an elliptical arc shape in cross section and adjacent to the opposite faces on which the GND electrode (12B) and the minus electrode (12C) are provided, in which biological data is measured using the plus electrode (12A), the GND electrode (12B) and the minus electrode (12C).