Disclosed is an apparatus for measuring sizes of a human body, such as the length of an arm, the size of a waist and the width of a shoulder, in the state that a person does not take off its clothes, using millimeter waves. The apparatus includes a plurality of millimeter-wave transmission/reception units, a rotation unit and a digital signal processing unit. The plurality of millimeter-wave transmission/reception units are arranged in a circular shape around an object to be measured, transmit a millimeter wave to the object to be measured, and receive a signal reflected or scattered by the object to be measured. The rotation unit rotates a circular structure in which the plurality of millimeter-wave transmission/reception units are arranged. The digital signal processing unit analyzes the object to be measured using size and phase information of the signal received by the plurality of millimeter-wave transmission/reception units.
