To allow a retrieval request program of a host terminal to automatically select a host computer for executing a retrieval based on a retrieval condition and to reduce retrieval time by distributing a load of the host computer.

A main host computer 1, a sub host computer 2 and a host terminal 3 are connected to one another by a network 4, wherein main data 5 and sub data 6 both of which are composed of the same, static data are managed by the main host computer 1 and the sub host computer 2, respectively. A retrieval request with an automatic host selection function and a data display program 11 possessed by the host terminal 3 determine on the basis of a host selection condition 13 to which of the main host computer 1 or the sub host computer 2 the retrieval request is preferentially sorted and given. A host selection condition is based on a retrieval time band, a required time or the like.