A data duplication device comprising: a range determination unit to determine a duplication range using a data processing graph indicating information of input/output data to and from a duplicate source program involved in a duplicate source system, the duplication range being a range of data to duplicate from the duplicate source system to a duplicate destination system; a data acquisition unit to acquire duplicate data corresponding to the duplication range from the duplicate source system; and a data registration unit to register the duplicate data with the duplicate destination system, wherein the data processing graph includes: a program node indicating the duplicate source program; an input information node indicating information of input data out of the input/output data to and from the duplicate source program; an output information node indicating information of output data out of the input/output data to and from the duplicate source program; a data range node indicating a data range of the input/output data to and from the duplicate source program; a table node indicating a duplicate source table involved in the duplicate source system; and links to connect the program node, the input information node, the output information node, the data range node, and the table node. a range determination unit to determine a duplication range using a data processing graph indicating information of input/output data to and from a duplicate source program involved in a duplicate source system, the duplication range being a range of data to duplicate from the duplicate source system to a duplicate destination system; a data acquisition unit to acquire duplicate data corresponding to the duplication range from the duplicate source system; and a data registration unit to register the duplicate data with the duplicate destination system, wherein the data processing graph includes: a program node indicating the duplicate source program; an input information node indicating information of input data out of the input/output data to and from the duplicate source program; an output information node indicating information of output data out of the input/output data to and from the duplicate source program; a data range node indicating a data range of the input/output data to and from the duplicate source program; a table node indicating a duplicate source table involved in the duplicate source system; and links to connect the program node, the input information node, the output information node, the data range node, and the table node. a program node indicating the duplicate source program; an input information node indicating information of input data out of the input/output data to and from the duplicate source program; an output information node indicating information of output data out of the input/output data to and from the duplicate source program; a data range node indicating a data range of the input/output data to and from the duplicate source program; a table node indicating a duplicate source table involved in the duplicate source system; and links to connect the program node, the input information node, the output information node, the data range node, and the table node.