To provide a fixing device which excels in fixing properties, even at non-hermal pressure fixing.

The fixing device includes an addition means for adding a pressure fluid accelerator to the unfixed image of a pressure fluid toner on a medium to be recorded, and a pressure fixing means for fixing the unfixed image on the medium to be recorded by pressure, wherein the pressure fluid toner contains a block copolymer, having at least two kinds of blocks of which the difference of glass transition temperature is 50 to 200°C and the pressure fluid accelerator is a compound satisfying the relation (1): SPL-1.0≤SPA≤SPL+1.0. In the relation, SPA represents the SP value (solubility parameter) of the pressure fluid accelerator and SPL represents the SP value of a block, having lower glass transition temperature of the two kinds of blocks of the block copolymer.