A measured antenna and a measuring antenna are placed inside a radio anechoic container. On the basis of an aperture size D of the measured antenna, an aperture size d of the measuring antenna, and a wavelength λ of a measurement frequency, a distance L between the measured antenna and the measuring antenna is set to a value in the range of (D+d)2/(2λ) to 2(D+d)2/λ. Thus, in the Fresnel region where the distance L is short, antenna characteristics of the measured antenna substantially the same as those in the Fraunhofer region where the distance L is long can be measured.