Fixing device for fixing toner to sheet

A fixing device, comprising:

• a cylindrical belt;
• a heater to heat the belt, the heater including (a) a base plate and (b) a heating element provided on the base plate, the heating element having a one-side end and an other-side end in a first direction;
• a holder supporting the heater;
• and
• a heat-conductive member disposed between the heater and the holder, the heat-conductive member having a heat conductivity higher than a heat conductivity of the base plate,
• wherein the heat-conductive member includes:
• a main portion that is opposed to a region of the base plate between the one-side end of the heating element and the other-side end of the heating element in the first direction;
• a first opposed portion that is opposed to a region of the base plate in which the one-side end of the heating element is located, and
• a second opposed portion that is opposed to a region of the base plate in which the other-side end of the heating element is located, and
• wherein each of a cross-sectional area of the first opposed portion and a cross-sectional area of the second opposed portion is smaller than a cross-sectional area of the main portion, each of the cross-sectional areas being an area of a cross section orthogonal to the first direction.