Route search systems, methods, and programs search for a recommended route using a cost value of a link or a node that constitutes a route. The systems, methods, and programs calculate the cost value of the link or the node on the basis of calculation material information that serves as a material for calculating the cost value, and specify a reliability degree of the calculated cost value of the link or the node on the basis of a number of pieces of the calculation material information used to calculate the cost value of the link or the node. The systems, methods, and programs correct the cost value of the link or the node, the reliability degree of which has been specified, on the basis of the specified reliability degree, and search for the recommended route using the corrected cost value.