A heater includes: a base body formed of ceramics; a heat generating resistor layer disposed on a surface of the base body; a conductive layer laminated on the heat generating resistor layer; a plate-like member which is disposed on the conductive layer and is provided with a pair of through holes; and a connection terminal composed of wires which are inserted successively through one of the pair of through holes and the other and are unified at a side of the plate-like member which side is opposite to a side of the plate-like member facing the conductive layer, the connection terminal being electrically connected with the conductive layer.