A long distance and expensive equipment is required for measuring a far-field of large aperture antenna. A method of the far-field estimation by simple measurement in a near-field area of a one-dimensional large aperture antenna is proposed. The method used an equivalent current distribution measured in a simple anechoic chamber. The proposed method is used an equivalent current distribution measured in a simple anechoic chamber. A vertical plane pattern and a horizontal plane pattern are estimated from a one-dimensional current distribution and a circular current distribution, respectively. For the directivity estimation error less than 0.5dB, a distance between AUT and measurement position is need about 0.3×wavelength. As the horizontal plane distance is required 0.1 × AUT width + 0.45 ×wavelength.