A ceramic substrate is provided that includes a ceramic substrate main body including a principal surface, a connecting terminal portion disposed on the principal surface of the ceramic substrate main body that is capable of being connected to another component via solder, the connecting terminal portion including a copper layer and a coating metal layer covering a surface of the copper layer; a contact layer of titanium or chromium disposed between the ceramic substrate main body and the connecting terminal portion; and an intermediate layer disposed between the copper layer of the connecting terminal portion and the contact layer, the intermediate layer including one of a titanium-tungsten alloy, a nickel-chromium alloy, tungsten, palladium, and molybdenum. The contact layer and the intermediate layer are set back from a side surface of the copper layer in a substrate plane direction.