To execute an effective operation in accordance with the connection state of an external peripheral equipment to an electronic circuit card device such as a PC card.

The connector terminal 11 for connecting the external peripheral equipment of the PC card 10 is provided with exclusive detecting terminals 31A, 31B and 31C for detecting the connection state of an external equipment in addition to the input terminals 21 and 22 of a video signal and an audio signal and detecting circuits 32A, 32B and 32C are respectively connected to the detecting terminals 31A, 31B and 31C. Detection outputs from the respective detecting circuits 32A, 32B and 32C are transmitted to an IREQ (interruption request) generating circuit 33 and an IREG register 34. The control circuit part 201 of a personal computer mainbody 100 reads the contents of the IREQ register 34 in accordance with the signal from the IREQ generating circuit 33, controls the validity/invalidity of a function in relation with the connected external peripheral equipment and also displays the state of validity/invalidity by a display processing part 202.