In a content distributing system, a feature amount distributing server 140 includes a processing information generation unit 141 which generates processing information, a feature amount extraction unit 112 which extracts a content feature amount from distributed contents, a processing unit 142 which processes the content feature amount and generates a processed feature amount, a selecting unit 143 which selects an evaluation feature amount from the content feature amount or the processed feature amount, and a distributing unit 144 that distributes the evaluation feature amount to a client 130. A monitoring server 117 has a warning unit which collates the processing information generated by the processing information generation unit 141 of the feature amount distributing server 140 and a quality evaluation value received from the client, and gives a warning when the processing information and the quality evaluation value are mismatched with each other.