An oven with a heat-circulating device includes a housing provided with a chamber for roasting and steaming; a motor fixed on a rear surface of a rear wall of the chamber; a fan; a heater; a separating plate positioned in front of the fan; a steaming device; a tray and a cover. The e annular heater and the fan fixed on an inner surface of the rear wall in front of the motor. The steaming device is composed of a connect tube, a pump motor, an outflow tube and a heating case for heating the water filled in the heating case for producing steam to be blown and circulated by the fan also blowing the hot air to circulate in a balanced condition around the chamber and a food placed to be roasted and steamed synchronously, with the food not losing all water contained.