To enable the route calculating device used for a vehicle distribution system to assign distribution spots to vehicles and calculate a route for making a round of the distribution spots fast with high precision.

A route cost calculating means 103 calculates the cost for new arrangement data, representing the order of spots that vehicles make a round of as an array of spot numbers, generated by a route new arrangement data generating means 102 by using an arrangement data conversion rule. An arrangement data selecting means 104 makes a choice of whether or not the new arrangement data are adopted according to the cost difference and search temperature and adjusts the choice strength of the arrangement data conversion rule according to the choice result. After a search process at current search temperature ends, a temperature update means 107 lowers the search temperature and the search process is repeated until the time when the cost for the arrangement data does not show variation. Thus, a repetitive improving method is used to efficiently generate new arrangement data and the proper cost of arrangement data is calculated to obtain a high-precision solution at a high speed.