A route information processing apparatus includes: a processor configured to execute a program; and a memory configured to store the program, wherein, based on the program, the processor performs operations to: calculate maximum values corresponding to a Frechet distance between one line segment of one or more line segments between observation points included in a trajectory and each of sets of two nodes corresponding to the one line segment, the nodes being included in a route graph including linked paths which link nodes; and acquire a path corresponding to the trajectory having a smallest value among the maximum values of the one or more line segments.