A board assembly including a cooling system includes: a wiring board; a first heat generating component mounted on a surface of the wiring board; a first heat receiving portion mounted on the first heat generating component and configured to allow a coolant to pass therethrough; a second heat generating component mounted on another surface of the wiring board; a second heat receiving portion mounted on the second heat generating component and configured to allow the coolant to pass therethrough; and a support post disposed through the wiring board so as to extend between the first heat receiving portion and the second heat receiving portion, the support post having a space through which the coolant flows from the first heat receiving portion to the second heat receiving portion or from the second heat receiving portion to the first heat receiving portion.