Provided is an antenna placement method in a system for detecting an object in a detection area between at least one set of a transmission station and a reception station by a wireless signal. The antenna arrangement method includes: making the transmission station having a plurality of antennas transmit a measurement signal for measuring channel state information; making the reception station having a plurality of antennas measure the channel state information based on the measurement signal and notify a detection server of a result of the measurement; and making the detection server perform processing where the detection server detects an object based on the channel state information, calculates at least one of a channel capacity and an eigenvalue distribution based on a propagation channel matrix between the transmission station and the reception station, and determines an antenna arrangement where the channel capacity becomes a largest or an antenna arrangement where spreading of the eigenvalue distribution becomes a smallest.