A synthetic reception strength value in a case of synthesizing indirect waves of radio waves generated due to an obstruction is calculated for each piece of receive antenna coordinate information in consideration of a phase of each indirect wave. Relation information indicating relation between input information and teaching information is generated. The input information is the synthetic reception strength value for each piece of the receive antenna coordinate information corresponding to transmit antenna coordinate information. The teaching information is information indicating a reception state of the radio waves being calculated using a method of actually measuring the radio waves output by the transmit antenna at a position of a receive antenna or a method other than the method of the actual measurement. Strength of the radio waves is estimated by calculating the information indicating the reception state of the radio waves by using the transmit antenna coordinate information for evaluation and the generated relation information.