Disclosed is a main board of a portable terminal including a socket receiving an additional device, such as a memory card and being installed at one side of the main board, an interface connector attached to a printed circuit board, and a battery terminal attached to the printed circuit board. The interface connector and the battery terminal form a stacked structure together with the socket. The main board of the portable terminal is provided at a predetermined portion thereof with a stacked structure of the socket for receiving the memory card, the interface connector, and the battery terminal, thereby minimizing mounting space required for the above elements, ensuring mounting space for installing other parts, and efficiently utilizing part mounting space. The socket and the interface connector are located adjacent to each other, and the socket and the interface connector are exposed through a common opening, thereby making the assembly for the portable terminal more efficient.