A cognitive function evaluation device includes an acquirer that acquires speech data that indicates speech uttered by an evaluatee in response to a task given to the evaluatee; an evaluator that evaluates a cognitive function of the evaluatee by performing a first evaluation based on a proportion of speaking time of the evaluatee in a predetermined period in the speech data acquired by the acquirer and a second evaluation based on a fundamental frequency in the speech data acquired by the acquirer; and an outputter that outputs an evaluation result obtained from the evaluation performed by the evaluator.