A character overlapping with a line of an entry box is extracted utilizing a dot box. At document input step S2, a document to be recognized is read and converted into electronic data to produce character box data. At electronic data storing step S3, the character box data read at the photoelectric transducing S2 is stored. At character detecting step S5, the character box data is contracted, small points are removed, and the remaining pattern is reversely expanded to produce character data. At entry box detecting step S4, entry box position data is generated from the character box data and character data. At relating step S6, a character pattern entered in each entry box is detected from the character data and the entry box position data. At character recognizing step S7, a character is recognized for the extracted character pattern and the results are stored at step S8.