Abstract: The present invention provides a heat developable light sensitive material comprising a support and a constituent layer disposed on one surface of the support and including a light sensitive layer, wherein the constituent layer includes a binder, an organic silver salt, a reducing agent for silver ion, light sensitive silver halide grains, and at least one polymer binder selected from a group consisting of polyvinyl butyral, cellulose acetate, cellulose butyrate and derivatives thereof, and a mercury content of the constituent layer is no more than 1 mg/m2, and a logarithmic value of the cross sectional resistance value (&OHgr;) of the light sensitive material is no more than 12, and a coated amount of silver is no more than 1.9 g/m2, and image forming methods using the above-described heat developable light sensitive material.