PURPOSE: To reduce cost, to facilitate the exchange of a data storage part and to improve convenience by connecting a control part and the data storage part by means of a connector which can be pulled out.

CONSTITUTION: A microcomputer part 2 is provided with a female pin receiving terminal 21 engaged with the connecting pin 11 of the connector 1 so that the microcomputer part can be connected with the connector 1 of a host device 10. The connector 1 has a form and structure to hold the microcomputer part 2 so that it can surely hold the whole memory card. Furthermore, the microcomputer part 2 has a pin connector 3 which can be connected with a memory pack 4. The pin connector 3 has the form and structure to hold the memory pack 4 so that it can surely hold the whole memory pack. The memory pack 4 is provided with the female pin receiving terminal 41 engaged with the pin of the connector 3. When the memory pack 4 is removed or exchanged, the microcomputer part 2 be connected to the host device 10 as it is.