PURPOSE: To eliminate the need of keeping the respective kinds of deformed stocks by the different coupling components of a board by providing first and second board coupling components respectively suitable for connecting the board to the computer of a first or second type and a switching means depending on the type of a computer to be connected.

CONSTITUTION: Board coupling components 2 and 3 respectively suitable for the connection to the matching coupling component of the first and second types of the computers are provided. Also, the respective board coupling components 2 and 3 are respectively provided with connection parts or connection areas 4 and 5 connected to the components 6 and 7 or the like of a circuit provided on the board 1 by the conductor of the board 1. Further, the board 1 is provided with the connection part 9 and provided with a detection conductor 8 connected to the switching means indicated by the component 6. The connection part 9 is suitable for performing the connection to a point in the computer provided with the potential characteristics of the type of the computer after the board 1 is attached inside the computer. Thus, the stocks of the respective kinds of the boards are reduced.