7. The document viewing device according to claim 6 , wherein said document data includes information specifying a prescribed object of said document data, in the process of determining whether the relevant page searched is checked or unchecked, the processing device determines whether the object included in the relevant page searched is checked or unchecked, and extracts the relevant page searched whose object is determined to be unchecked, and in said process of extracting the page for which it is determined that the object is unchecked, said processing device determines based on said viewing history based on the designation specifying the position of said document received by said input device whether each said prescribed object is checked or unchecked by said user.
9. The document viewing device according to claim 7 , wherein in said process of generating the viewing history, said processing device records display time as said viewing history for each page displayed on said display device, and in said process of extracting the page for which it is determined that the object is unchecked, said processing device compares said display time with reference time stored in advance for each page of said document, to determine for each said page whether the object is checked or unchecked by said user, and extract the page that includes said prescribed object determined as being unchecked and is determined as being unchecked by said user from pages each searched for as being relevant to the object displayed on said display device.