DRIVING ASSISTANCE DEVICE AND DRIVING ASSISTANCE METHOD

A driving assistance device includes: a sight line detector that detects a sight line of a first user driving a first vehicle; a feature detector that detects a feature in a vicinity of the first vehicle; a visual recognition determiner that determines whether the first user visually recognized the feature, based on the sight line detected and the feature detected; a position detector that detects a first position of the first vehicle; an obtainer that obtains a second position that a second vehicle was at when a second user driving the second vehicle visually recognized the feature in past; and an alerter that performs, at a timing determined based on a result of comparison between the first position and the second position, alerting to prompt the first user to visually recognize the feature, when the visual recognition determiner determines that the first user has not visually recognized the feature.