A fixing device includes: a fixing belt in an endless form; a fixing roller; a separating roller for separating, from the fixing belt, a paper sheet onto which a developer is fixed and fused; a heating roller for heating the fixing belt; a pressurizing roller for forming a fixing nip portion between the fixing belt and the pressurizing roller; a first lever to which the fixing roller and the separating roller are fixed, the first lever pivoting around a first supporting point used as the center point; a second lever to which the fixing roller and the heating roller are fixed, the second lever pivoting around a second supporting point used as the center point; a first spring for biasing the first lever; and a second spring for biasing the second lever.