Provides is an apparatus for question answering based on answer trustworthiness including: an answer indexer that indexes documents of which document trustworthiness satisfying a threshold value among documents included in a document collection and stores it in a knowledge Bases; an answer candidate extractor that extracts answer candidate documents for a user's question from the knowledge Bases; an answer source trustworthiness measurement unit; an answer extraction strategy trustworthiness measurement unit; and a trustworthiness integrator that generates an answer candidate trustworthiness list by ranking the answer candidate documents on the basis of the document trustworthiness, the source trustworthiness, and the extraction strategy trustworthiness of the answer candidate documents.