When a CSV, (Comma Separated Value Format) mode is set up, document-string data of the CSV type received from an external apparatus on-line is stored in a reception buffer. When data is read from the reception buffer, character data in each print block other than quotation marks (") and commas (,) indicating separation between data are stored in a text memory. When a print format is set up for each stored print block, the data related to the format is stored in the text memory. When, a line-feed code is detected, the characters are printed on a printing tape according to the data related to the format and character data stored in the text memory.