A search apparatus includes a memory and circuitry. The memory is configured to store second sentences in association with past-input first sentences, and store synonyms corresponding to each of a plurality of words. The circuitry is configured to divide each of the past-input first sentences into words and divide a newly-input first sentence into words; select, from the synonyms corresponding to each of the plurality of words, synonyms corresponding to each of the words obtained by dividing each of the past-input first sentences, in descending order of appearance frequency of the words; store the selected synonyms; detect, from the selected synonyms, synonyms corresponding to each of the words obtained by dividing the newly-input first sentence; and retrieve, from the memory storing the second sentences, at least one of the second sentences corresponding to the newly-input first sentence based on the detected synonyms and the words of the newly-input first sentence.