A failure cause estimation device includes: a database that manages the causes of failure cases, questions, and replies thereto for each of the failure cases; a condition presentation unit that presents combinations of the questions and replies managed in the database on a display screen as branch conditions used to classify the cause of a failure case; a condition selection unit that selects at least one branch condition from the presented branch conditions according selection operation; a cause estimation unit that estimates a cause satisfying the at least one branch condition from the contents of the database; and a cause presentation unit that presents the estimated cause on the display screen as a cause candidate.