A fixing unit for an image forming apparatus using electrophotography comprising: a rotatable heating roller for heating a recording medium on which a developer image is formed, said heating roller including a core being elongated in an axial direction of the heating roller and a resilient body formed around said core; a first pressure member (32, 32A) for pressing said recording medium against said heating roller, said first pressure member (32, 32A) being elongated in the axial direction, said first pressure member (32, 32A) including a first pressing portion having higher hardness than said resilient body, wherein a first center portion (32t, 32At) of said first pressing portion in the axial direction protrudes toward said heating roller more than first end portions (32s, 32As) of said first pressing portion; a second pressure member for pressing said recording medium against said heating roller, provided on an upstream side of said first pressure member (32, 32A) in a conveying direction of said recording medium, said second pressure member being elongated in the axial direction, said second pressure member including a second pressing portion having higher hardness than said resilient body, wherein a second center portion of said second pressing portion in the axial direction protrudes toward said heating roller more than second end portions of said second pressing portion, and a fixing belt stretched around said first and second pressure members (32, 32A, 33) and nipped between said heating roller and either of said first and second pressure member (32, 32A, 33), wherein said resilient body is deformed by being pressed by said first pressure member (32, 32A) so that a first rotation radius of said heating roller at said first center portion (32t, 32At) of said first pressure member (32, 32A) is smaller than a second rotation radius of said heating roller at said first end portions (32s, 32As) of said first pressure member (32, 32A); wherein said resilient body is deformed by being pressed by said second pressure member so that a third rotation radius of said heating roller at said second center portion of said second pressure member is smaller than a fourth rotation radius of said heating roller at said second end portions of said second pressure member. a rotatable heating roller for heating a recording medium on which a developer image is formed, said heating roller including a core being elongated in an axial direction of the heating roller and a resilient body formed around said core; a first pressure member (32, 32A) for pressing said recording medium against said heating roller, said first pressure member (32, 32A) being elongated in the axial direction, said first pressure member (32, 32A) including a first pressing portion having higher hardness than said resilient body, wherein a first center portion (32t, 32At) of said first pressing portion in the axial direction protrudes toward said heating roller more than first end portions (32s, 32As) of said first pressing portion; a second pressure member for pressing said recording medium against said heating roller, provided on an upstream side of said first pressure member (32, 32A) in a conveying direction of said recording medium, said second pressure member being elongated in the axial direction, said second pressure member including a second pressing portion having higher hardness than said resilient body, wherein a second center portion of said second pressing portion in the axial direction protrudes toward said heating roller more than second end portions of said second pressing portion, and a fixing belt stretched around said first and second pressure members (32, 32A, 33) and nipped between said heating roller and either of said first and second pressure member (32, 32A, 33), wherein said resilient body is deformed by being pressed by said first pressure member (32, 32A) so that a first rotation radius of said heating roller at said first center portion (32t, 32At) of said first pressure member (32, 32A) is smaller than a second rotation radius of said heating roller at said first end portions (32s, 32As) of said first pressure member (32, 32A); wherein said resilient body is deformed by being pressed by said second pressure member so that a third rotation radius of said heating roller at said second center portion of said second pressure member is smaller than a fourth rotation radius of said heating roller at said second end portions of said second pressure member.