For a soft error of an electronic device, a technique capable of ensuring high reliability because of a low soft error rate (SER) is provided. By using building data including information of a structural object of a building and facility data including information of a plurality of facilities including an electronic device arranged in the building, a SER calculating device calculates a model including an attenuation index value representing a degree of attenuation of radiation entering the building attenuated by the structural object of the building until the radiation reaches a position of the facility arranged in the building, calculates a SER at each position of the facility arranged in the building by using the model including the attenuation index value, and outputs information including the SER at each position of the facility.