To provide a header sheet and a header sheet processing method for preventing the data of a gift certificate from being added to the data of the gift certificate read by the previous reading processing even when a machine reading device is made to read a header sheet whose back side is turned upside down as a front side by mistake.

An identification code showing that reading processing by a reading device is interrupted is displayed so as to be machine readable on the back face of a header sheet. This header sheet processing method includes a step for reading display for machine reading displayed on the face of the header sheet by a machine reading device; a step for determining whether or not display for the machine reading is the identification code showing that the reading processing by the reading device is interrupted; and a step for performing processing to interrupt the reading processing of the machine reading device when it is determined that the display for machine reading is the identification code showing that the reading processing by the reading device is interrupted.