A method of evaluating corrosion in which evaluation for corrosion is performed on the basis of a result of measurement performed on the corrosion of a metal material, comprising: acquiring (S 1) a first measurement result performed by a plurality of first detectors (1031-1033, 1071-1073), each of the first detectors (1031-1033, 1071-1073) being installed at a respective measuring point of a plurality of first measurement points; acquiring second measurement results performed by one or more second detectors (1031-1033, 1071-1073), each of the second detectors (1031-1033, 1071-1073) being installed at a respective measuring point of one or more second measurement points that are different from the first measurement points; acquiring an estimation result in which information on a measurement result at an estimation point that is different from the first measurement points and the one or more second measurement points is estimated; and performing the evaluation for corrosion on an area including the first measurement points, the second measurement points, and the estimation point on the basis of the first measurement result, the second measurement results, and the estimation result, characterized in that the evaluation for corrosion is performed on the basis of the result of measurement performed on the corrosion of the metal material using the plurality of first detectors (1031-1033, 1071-1073) and the one or more second detectors (1031-1033, 1071-1073), the plurality of first detectors (1031-1033, 1071-1073) being used to estimate information on the measurement result at the estimation point, and the one or more second detectors (1031-1033, 1071-1073) not being used to estimate the information on the measurement result at the estimation point, wherein each of the one or more second measurement points is a point on a region having a special corrosiveness in the area, the region being any one of a vicinity of a river, a river crossing place, an industrial waste disposal site, or a vicinity of an incinerator, a place at which snow melting salt has been scattered on a main road, a place at which fog or sea fog occurs for a long time. acquiring (S 1) a first measurement result performed by a plurality of first detectors (1031-1033, 1071-1073), each of the first detectors (1031-1033, 1071-1073) being installed at a respective measuring point of a plurality of first measurement points; acquiring second measurement results performed by one or more second detectors (1031-1033, 1071-1073), each of the second detectors (1031-1033, 1071-1073) being installed at a respective measuring point of one or more second measurement points that are different from the first measurement points; acquiring an estimation result in which information on a measurement result at an estimation point that is different from the first measurement points and the one or more second measurement points is estimated; and performing the evaluation for corrosion on an area including the first measurement points, the second measurement points, and the estimation point on the basis of the first measurement result, the second measurement results, and the estimation result, the evaluation for corrosion is performed on the basis of the result of measurement performed on the corrosion of the metal material using the plurality of first detectors (1031-1033, 1071-1073) and the one or more second detectors (1031-1033, 1071-1073), the plurality of first detectors (1031-1033, 1071-1073) being used to estimate information on the measurement result at the estimation point, and the one or more second detectors (1031-1033, 1071-1073) not being used to estimate the information on the measurement result at the estimation point, wherein each of the one or more second measurement points is a point on a region having a special corrosiveness in the area, the region being any one of a vicinity of a river, a river crossing place, an industrial waste disposal site, or a vicinity of an incinerator, a place at which snow melting salt has been scattered on a main road, a place at which fog or sea fog occurs for a long time.