Various types of thermal heads have been heretofore proposed as printing devices for a facsimile, a video printer or the like. For example, a thermal head described in Patent Literature 1 includes a substrate, a thermal storage layer disposed on one main surface of the substrate so as to extend to an edge of the substrate, the thermal storage layer being made of glass, electrodes disposed above the thermal storage layer apart from the edge of the substrate, heat-generating resistors connected to the electrodes, a covering layer disposed on the electrodes and the heat-generating resistor and a protection film disposed on the covering layer (for example, refer to Patent Literature 1).