A coffee roasting apparatus is disclosed. The coffee roasting apparatus comprises a cylindrical container, a cylindrical drum rotatably extended within the center portion of the container, and a heater element diposed within the drum. The apparatus includes a blower device to cause air circulation within the interior of the container to more uniformily heat the beans. The heater element is controlled by a control device to reduce the calorific value of the heater element when the temperature of the container reaches a predetermined temperature. Therefore, abnormal temperature in the container is prevented, while the roasting operation is speedily done. A control device for the blower device is also disclosed which will vary the speed of the blower in response to changes in the input voltage. In this way, an increase in the input voltage which may have caused unwanted overheating is avioded by a corresponding increase in air circulation.