Disclosed is a fixing device including a liquid supply unit that supplies a liquid fixer containing a softening agent that dissolves or swells at least part of resin to soften the resin; an air supply unit that supplies air for foaming the liquid fixer; and a foam generation unit that mixes the liquid fixer from the liquid supply unit with the air from the air supply unit to generate foams. The foam generation unit has an air channel where the air from the air supply unit flows, a liquid-fixer channel provided such that the liquid fixer from the liquid supply unit flows from a direction opposite to a flowing direction of the air channel, and an air-and-liquid mixing part that mixes the air from the air channel with the liquid fixer from the liquid fixer channel so as to be opposite to each other, thereby generating a foam-like fixer.