A guidance assistance apparatus includes: a memory that stores a set of instructions; and at least one processor configured to execute the set of instructions to: acquire a guidance route through which a guided person is to be guided from routes from a start-point position to an end-point position; calculate, based on information relating to the routes, an influence level on the guided person in a case in which the guided person deviates from the acquired guidance route, with respect to each of branch places at which the guidance route branches into a route different from the guidance route; and output the calculated influence level.