A routing apparatus that determines a path for a flow in a network including a plurality of data links, the routing apparatus including: a constraint condition setting unit configured to generate a constraint condition that has a requirement that an end-to-end quality requirement of the flow is satisfied based on a quality variation occurring in each of the data links owing to the allocation of the flow to each of the data links and another requirement that an end-to-end quality requirement of another flow existing in each of the data links is satisfied based on a quality variation occurring in the another flow owing to the allocation of the flow to each of the data links; and a routing unit configured to determine the path for the flow from among a plurality of paths including the data links within a range satisfying the constraint condition.