To provide an information processor capable of dealing with the increment of progress sorts to be managed by making the processor capable of recording the progress history of transaction information in every slip, optionally executing correcting/canceling processing in the continuously generated processing of the same sort and corresponding.

When a record correcting/canceling instruction is inputted from an input device 3 in record correcting/canceling processing as processing related to transaction processing, a CPU 2 retrieves a record having the highest processing order from a progress management file stored in a storage device 7, and when the processing order of the retrieved record is higher than that of a record to be corrected/canceled, disables the correcting/canceling processing. When the processing order of the retrieved record is the same or lower than that of the record to be corrected/canceled, the correcting/canceling processing is permitted.