An induction-heating cooker has a top plate on which a cooking container is placed, a heating coil disposed below the top plate, an insulation plate on which the heating coil is placed, a ferrite on which the insulation plate is placed, a metallic magnetic shield plate on which the ferrite is placed, an infrared sensor arranged below the magnetic shield plate to detect an infrared ray radiated from the cooking container, a casing having at least a bottom part located below the infrared sensor and a side wall part extended upward from the bottom part so as to surround the infrared sensor and made from an electrically conductive material, and a spacer intervening between the lower surface of the magnetic shield plate and the upper end of the casing in contact with both these surfaces and made from a material having electrical insulation.