PROBLEM TO BE SOLVED: To estimate the position of an article with a radio tag attached thereto regardless of the arrangement, outer appearance, packing state, etc., of the article. SOLUTION: This radio tag position estimation system is provided with radio tag communication equipment for transmitting and receiving information to/from a radio tag by radio communication, and a radio tag position estimating device for estimating the position of the radio tag on the basis of information from the radio tag communication equipment. The radio tag communication equipment has a means for emitting a radio wave from a prescribed position in a prescribed direction to transmit a signal to the radio tag, and a means for receiving a response signal from the radio tag with respect to the emission of the radio wave. The radio tag position estimating device has a means for estimating whether to receive a response from the radio tag in the case of communicating from which position in which direction on the basis of the information received by the radio tag communication equipment, and a means for estimating the position of the radio tag on the basis of a plurality of pieces of estimated information. COPYRIGHT: (C)2008,JPO&INPIT