A route allocation apparatus includes a route calculation section and a route allocation controller. The route calculation section calculates a route between an outgoing edge node and incoming edge node within a network. The route allocation controller allocates the route to communication slots. Further, the route allocation controller calculates an expected value as an index of the number of the routes allocatable to the communication slots, selects a route allocation in which the expected value is a maximum, obtains the number of the routes allocatable to the selected communication slots after the route allocation, and updates the expected value.