A running method determination device includes at least one processor that executes a program stored in at least one memory. The at least one processor acquires motion data at a time of running of a user, calculates, based on acceleration data in multiple axial directions included in the acquired motion data, a sum of acceleration vectors in the multiple axial directions as a resultant vector, and determines a type of a running method of the user using at least an angle of the calculated resultant vector as a standard of determination.