The following units are included: a word search unit searching a database for each of words included in an input word pair; a word vector extracting unit extracting a word vector corresponding to each of the searched words from a word vector database; a character vector converting unit converting characters included in the word pair into a character vector; a feature amount acquiring unit acquiring a feature amount by combining the extracted word vector of each of the words and the character vector generated by converting the characters; and an estimation unit estimating a semantic relation between the words from the acquired feature amount.