According to one embodiment, a cooling device includes a heat diffusion plate, a heat receiving portion, a heat sink and a heat pipe. The heat receiving portion is provided on the heat diffusion plate and thermally connected to an object to be cooled. The heat sink is provided on the heat diffusion plate, and it releases the heat of the heat receiving portion to outside. The heat pipe has a first end portion to be connected to the heat receiving portion and a second end portion located on an opposite side to the first end portion and to be connected to the heat sink.