A risk-of-falling determination apparatus includes a walk information obtainer that obtains walk information of a user, a myoelectric sensor that measures a first myoelectric potential difference on an anterior surface of a thigh of the user and a second myoelectric potential difference on a posterior surface of the thigh, a control circuit that identifies an interval of a stance phase by using the walk information, calculates a degree of co-contraction at a corresponding leg of the user on the basis of the first and second myoelectric potential differences for the stance phase, and determines whether the degree of co-contraction is greater than or equal to a first threshold, and an outputter that outputs a signal indicating that the user has a high risk of falling if the degree of co-contraction is greater than or equal to the first threshold.