A fixing device comprises a fixing film for heating to fix a toner image formed on a recording material and a first fixing heater having a high heat generating region at a center portion where a heat generation amount is high. The fixing device also comprises a second fixing heater having a low heat generating region at the center portion where the heat generation amount is low. The fixing device also comprises a center portion temperature detection unit for detecting a temperature of the center portion of the fixing film, an end portion temperature detection unit for detecting a temperature of the end portion of the fixing film, a size detection unit for detecting a size of the recording material, and a control circuit unit.