Embodiments of the present invention relate to a board cooling apparatus comprising a shell and a board, where the board and an interior wall of the shell form a closed space, a cooling medium inlet and a cooling medium outlet are disposed on the shell, a separator plate that separates the board into a first part and a second part, a through opening between the first part and the second part, a cooling medium flows into the first part from the cooling medium inlet and then flows into the second part, and flows out from the cooling medium outlet, a flow guiding mechanism that is disposed on the board and configured to divert the cooling medium flowing into the first part from the cooling medium inlet, so as to directly guide part of the cooling medium into the second part.