To enhance the accuracy of a learner in semi-supervised learning, learning means of a learning system (S) causes the learner, which is configured to classify symbol information included in each of a plurality of documents, to learn based on training data indicating an attribute value of each of a plurality of attributes. Acquisition means inputs each of the plurality of documents to the learner to acquire the symbol information classified by the learner as an attribute value candidate. Determination means determines whether a symbol or a symbol string indicated by the attribute value candidate satisfies a predetermined condition. Additional learning control means controls, based on a determination result obtained by the determination means, additional learning by the learner using the attribute value candidate.