1. A handwriting processing apparatus comprising: a storage unit configured to store a character code of each character contained in a character string, with handwriting trail data of a handwritten character corresponding to a recognition disable code if the character code includes the recognition disable code; an input unit configured to input a handwritten character for search; a dictionary configured to store a shape of each of a plurality of characters; a recognition unit configured to recognize a corresponding character in said dictionary with respect to the handwritten character for search based on a similarity between the handwritten character for search input to said input unit and the shape of each of the characters stored in said dictionary; an assignment unit configured to assign a recognition disable code to the handwritten character for search as a character code if the similarity is less than a reference value and assign a text code of the corresponding character to the handwritten character for search as a character code if the similarity is not less than the reference value; and a search unit configured to search for data stored in said storage unit by using the assigned character code, wherein if the assigned character code includes the recognition disable code, said search unit executes search based on a similarity between handwriting trail data of the handwritten character for search and the handwriting trail data stored in said storage unit corresponding to the recognition disable code.