PURPOSE: To improve operability by attaching/detaching a memory card while a power source is turned on by setting an external input/output circuit to a conductive cut-off state corresponding to the non-mounting of the memory card at the time of turning on the power source, and holding such a state until confirming the mounting of the memory card.

CONSTITUTION: When the power source is turned on, first of all, a card detecting means 26 detects the mounting state of the card and when the mounting of the card is detected, a pattern selection mode is started. With the operation of a pattern selecting means 6, embroidery sewing due to external data or pattern sewing due to incorporated pattern group data is enabled. On the other hand, when the non- mounting of the card is detected, the signal circuit and power source supply of an external data input/output circuit 8 are cut off by operating an external input/output cut-off circuit 11. Afterwards, a memory card 9 is mounted and when a card mounting confirmation key is operated, the cut-off state of the external input cut-off circuit 11 is released. Then, the signal circuit and power source supply to the external data input/output circuit 8 are recovered, and the pattern group display data of the memory card 9 are displayed on a pattern display means 13.