The invention intends to provide, in BaTiO3 semiconductor porcelain composition, a semiconductor porcelain composition that, without using Pb, can shift the Curie temperature to a positive direction and can significantly reduce the resistivity at room temperature. According to the invention, when Ba is partially substituted by an A1 element (at least one kind of Na, K and Li) and an A2 element (Bi) and Ba is further substituted by a specific amount of a Q element, or when Ba is partially substituted by an A1 element (at least one kind of Na, K and Li) and an A2 element (Bi) and Ti is partially substituted by a specific amount of an M element, the optimal valence control can be applied and whereby the resistivity at room temperature can be significantly reduced. Accordingly, it is optimal for applications in a PTC thermistor, a PTC heater, a PTC switch, a temperature detector and the like, and particularly preferably in an automobile heater.