An occupant determination apparatus includes a load sensor that detects weight of an occupant seated on a seat of a vehicle, and a determinator determining the weight of the occupant as one status among a plurality of statuses which is set corresponding to the weight based on the measurement weight measured by the load sensor. In a case where an absolute value of acceleration acting on the vehicle becomes equal to or larger than the threshold value set in advance, the determinator determines the weight of the occupant as one of the status among the plurality of statuses based on the measurement weight measured before it becomes the threshold value.