PURPOSE: To attain rapid and accurate operation by finding out a message number string at the time of generating an operation error, successively generating messages to instruct the cause of the error and an error recovery method.

CONSTITUTION: Cash is registered by a registering circuit 1-2 through a keyboard 1-1. When misoperation is detected, the detected contents are analyzed by a check circuit 1-3 and an analyzed result is sent to a voice message collating circuit 1-4 as an error code to form a voice pattern. At that time, a message corresponding table 1-6 is searched by an error number to find out a message number string and voice data are formed by using a message table 1-7. The voice data are sent to a voice generating circuit 1-8 to generate voice. The code analyzed by the circuit 1-3 is simultaneously sent to a display message collating circuit 1-5 and display data are formed similarly to the voice case and sent to a display device 1-9.