To provide a simulation system capable of easily calculating a loading size of a pallet and the loading efficiency by a unit of pallet only by dialogically inputting the data of a basic size of a package and the like in a stage of planning the package for designing the optimum package in view point of physical distribution efficiency.

In this system for simulating the physical distribution loading efficiency of package boxes of commodities by dialogical operation, by accessing a server device from a client computer operated by a worker through a network, a size of each box, the packing number of the boxes to a makeup box, the packing number of the makeup boxes to an outer box, and a loading method to the pallet are successively designated to the server device by this order, whereby the loading efficiency in physical distribution is calculated, and its result is outputted to the client computer.