The primary object of the present invention is to provide an inexpensive fryer, and a further object is to improve thermal efficiency and make cleanup easier. A box-shaped oil vat 10 in which cooking oil is filled has a bottom wall portion 11 that is formed sloping downward toward the rear of the fryer. A burner 20 is provided at the bottom wall portion 11, with which a wide heating area can be secured. An exhaust duct 30 for conveying combustion gas from the burner 20 to the outside the fryer is provided around the oil vat 10 for securing the heated area. With this configuration, it is possible to inhibit the radiation of heat from the cooking oil while promoting the heat exchange between the combustion gas and the cooking oil. Moreover, the cooking oil can be adequately heated by simply providing a single burner 20, so manufacturing costs are not increased.