To prevent uneven developing resulting from the contact of recording material in a developing progressing temperature with the other members and to provide an image having uniform picture quality.

Recording material A is brought into contact with a heating means 68 in a heat developing portion 18 so as to provide a visible image in this device 10. A carrying means 140 grasping recording material A after heat developing and discharging outside the heat developing portion is disposed parting from the separation place 72 of the heating means 68 and the recording material A by a distance H equivalent to a time for cooling the material A down to such a temperature or less as the progressing of the developing stops.