PURPOSE: To prevent a document and a graphic from being mutually broke by printing out a mutually superposed part between a document print and a graphic print as a void.

CONSTITUTION: This document preparing device is provided with an input means 12 for inputting input data consisting of document input data and graphic input data, a 1st reading means for reading out document data of respective storage parts 14, 15 at the time of inputting the document input data to the means 12, a 2nd reading means for reading out graphic data from the storage parts 14, 15 at the time of inputting the graphic input data to the means 12, a void means for extracting a superposed part between the document data and the graphic data as a void when both the data read out of the storage parts 14, 15 are displayed in the partially superposed state, and a printing means 21 for printing out void data extracted by the voiding means on printing form.