Writing incorrect information to an IC tag affixed to a label is prevented. When a control command including recording information, an instruction to print the recording information on a label, and an instruction to write data including at least time-related information to an IC tag affixed to the label is received from a host computer, the system controller of a label printer prints the recording information and writes the write data based on time information input from a RTC, but does not print the recording information and write the write data based on the control command if an error was detected by RTC error detector.