A fixing device (15) of the present invention includes a fixing roller (30) having a fixing belt (35) heated by a heat source (32) around an outer circumference of an elastic layer (34) provided around a core metal (33); and a pressuring roller (31) provided so as to pressure-contact with the fixing roller (30) and to form a fixing nip (N) passing a recording medium (P) having a toner image transferred through, wherein, in both end faces (S1) in an axial direction of the elastic layer (34), annular gaps (70) are recessed separate from the core metal (33) and fixing belt (35) along a circumference direction, bottom parts (71) of the annular gaps (70) are configured so as to be positioned inside both end faces (S3) in the axial direction of the pressuring roller (31).