A ceramic substrate is provided, including: a board having a first surface and a second surface opposing the first surface; first electrical contact pads disposed on the first surface; second electrical contact pads disposed on the second surface; conductive pillars disposed in the board and connecting the first surface and the second surface to electrically connect the electrical contact pad and the second electrical contact pad; a first heat conductive pad disposed on the first surface; a second heat conductive pad disposed on the second surface; and a heat conductive pillar disposed in the board and connecting the first surface and the second surface to contact and be coupled with the first heat conductive pad and the second heat conductive pad, wherein the heat conductive pillar has a width greater than or equal to widths of the conductive pillars and greater than or equal to 300 micrometers.