PURPOSE: To uniformly heat a photosensitive material and to carry out the nonuniformity-free development without taking a contact resistance between an electrode and a member into consideration by employing an electromagnetic induction heating for a heating part when a heat development photosensitive material is heated.

CONSTITUTION: Since a rotary drum 21 wound with the heat development photosensitive material is provided with drive system pulleys 30, 32, 36 and 46, a belt 34, a tension device arm 40 and spring 44, a less-play synchronizing operation with respect to a drive motor 28 can be expected. A piece of information scanned by an original reader 58 is sequentially radiated from an exposure heat 54 through a high frequency oscillator 62, and accordingly the heat head 56 uniformly heats the heat development photosensitive material, which can be developed without unevenness. Simultaneously no electric shock preventing measure is necessary. Namely, the heat head 54 is caused to generate an induction eddy current to make an electrode, etc., normally used unnecessary, and heating is uniformly attained.