An occupant assist apparatus (12) has: a receiving device (121) for receiving an occupant information relating to an occupant of a vehicle; an estimating device (122) for estimating, on the basis of the occupant information, at least one of a desire of the occupant to urinate and a desire of the occupant to defecate in a future than a timing when the occupant information is received; and an executing device (123) for executing an occupant assist on the basis of a result of an estimation by the estimating device.