1. A data distributed search system comprising: a management computer including a processor and a memory; a plurality of search execution computers each including a processor and a memory; and a network connecting the management computer and the plurality of search execution computers, wherein the management computer includes: a distributed administration manager for receiving graphs, each of the graphs holding at least one relation connecting a data value with another data value and being composed of data pieces connected by the at least one relation, and distributing the graphs to the plurality of search execution computers; and a distributed search manager for sending search conditions to the plurality of search execution computers upon receipt of the search conditions and receiving search results from the plurality of search execution computers, wherein each of the search execution computer includes: a graph storage module for storing graphs received from the management computer; and a search execution module for searching the graphs with the search conditions received from the management computer and returning a search result to the management computer, wherein the distributed administration manager of the management computer classifies graphs including at least one common relation as a group and distributes and allocates the graphs belonging to the group to the plurality of search execution computers, wherein the distributed search manager of the management computer sends search conditions including a search condition on data relation and a search condition on data value to each of the plurality of search execution computers to request to conduct a parallel search, wherein the search execution module in each of the plurality of search execution computers extracts graphs matching the search condition on data relation as possible solutions and conducts condition matching on data values included in the graphs extracted as possible solutions with the search condition on data value to acquire a data piece of which the data value matches the search condition on data value as a search result.