1. A radio wave propagation characteristic estimation apparatus comprising: at least one processor communicatively coupled to a network, wherein the at least one processor is configured to: determine, for each of groups of combinations of measurement conditions classified in accordance with a measurement condition, an optimum radio wave propagation characteristic estimation technique from among a plurality of radio wave propagation characteristic estimation techniques, based on an actual measured value of radio waves, wherein the plurality of radio wave propagation characteristic estimation techniques include at least one of a ray tracing method, an Okumura-Hata method, and a plane-earth propagation model method; discriminate a group corresponding to a given measurement condition; set an optimum radio wave propagation characteristic estimation technique corresponding to the discriminated group; and estimate radio wave propagation characteristics in accordance with the set radio wave propagation characteristic estimation technique, wherein the measurement condition comprises at least one of a frequency of the radio waves, an above-ground level of a transmission antenna, and a distance between a transmission point and a reception point.