A food fryer allowing a fried food tank to be safely and efficiently cleaned, wherein an opening part (5a) is formed in the side upper part of an oil storage tank (5) so that an upper end part (5c) covers a lower end part (5b) a cock (5d) is installed at the bottom part of the tank, the opening part (5a) is positioned near a boundary between an oil tank area (1) and a water tank area (2), a cover part is not provided for the opening part, after a food frying operation is completed, first oil in the oil tank area (1) is stored in the oil storage tank (5) through the opening part (5a) by the opening and closing operation of the cock (5d) and then a cock (11) is opened to drain the oil from those portions other than the oil storage tank of the fried food tank (B), and the tank is cleaned, and when the next frying operation is started, the oil in the oil storage tank (5) is moved to the oil tank area (1) due to a difference in gravity between the oil and water by merely feeding the water into the fried food tank (B).