1. An address reader method of recognizing a receiver address on a surface of mail, said address reader method comprising: inputting an image of the surface of mail; segmenting said image into at least one character string candidate; extracting at least one address area candidate based on said at least one character string candidate; selecting one of said at least one address area candidate as a receiver address area of the mail by analyziing each of said at least one address area candidate based on predetermined position information indicating a usual position of a receiver address area, character direction information indicating a character direction of a character string appropriate for said predetermined position information, and key character string information indicating a character string most likely to exist in a receiver address; and recognizing characters in character strings of the selected address area candidate as a receiver address.