By preheating temperature raising unit of a steam and hot water generating device beforehand to a predetermined temperature, and supplying water in an amount equal to or more than predetermined amount V (per unit time) to the temperature raising unit, a large amount of steam is instantaneously generated. At this time, hot water adhered to the temperature raising unit rises along with the steam, and the steam and hot water flowed through a steam hole, a relay tube, and a steam chamber are caused to eject instantaneously with accumulated steam pressure from a steam and hot water discharging port. The steam and hot water then hit and heat food products accommodated in a cooking chamber. Thus, a heating cooker capable of promptly heating a food product with steam can be provided.
