In case a similar component-to-be-loaded is erroneously loaded on a main body side apparatus, contact of terminals are avoided. To this end, a video camera (main body side apparatus) 1 has a main body side terminal 30, and a battery pack (component-to-be-loaded) 100 has a battery side terminal (component-to-be-loaded side terminal) 120. In the vicinity of the battery side terminal of the component-to-be-loaded, a discriminating tab 111 is provided, and a blocking portion 19 is provided in the vicinity of the main body side terminal of the video camera (main body side apparatus) for determining whether or not its loading is permitted based on the combination of concave and convex engagement with respect to the above-mentioned discriminating tab, and when the loading is not permitted due to the interference between the blocking portion and the above-mentioned discriminating tab, an electric connection between the main body side terminal and the battery side terminal (component-to-be-loaded side terminal) is not to be established.