A server includes an adapter device, multiple storage modules and multiple controllers. The adapter device includes a base circuit board having opposite first and second surfaces, multiple first connectors disposed on the first surface along a first direction and connected to the base circuit board, and multiple second connectors disposed on the second surface along the first direction in pairs, each of which is arranged along a second direction, is connected to the base circuit board and is disposed between adjacent two of the first connectors. Each of the storage modules is connected to a corresponding first connector. Each of the controllers is connected to a corresponding second connector.