A fixing device includes a heat unit that heats a toner image on a first recording medium and a heat absorption and transmission unit that absorbs heat of the first recording medium sent from the heat unit and transmits the heat thus absorbed to a second recording medium to be sent to the heat unit. The heat absorption and transmission unit includes a belt member circulated around tensile members to transport the first and second recording media. The belt member has a heat absorption portion and a heat transmission portion downstream and upstream from the heat unit, respectively. The heat absorption portion contacts the first recording medium and absorbs heat in a state that periphery of a contact region is thermally insulated, and the heat transmission portion contacts the second recording medium and transmits heat in a state that a periphery of a contact region is thermally insulated.