a film transporting device to transport a heat developable photosensitive film one at a time;

an exposing device to form a latent image on the film based on predetermined testing exposure data or diagnostic image data;

a heat developing device to heat-develop the latent image on the film, for visualizing the latent image;

a density measuring device to measure the density of the visualized image after the heat development; and

a controlling device to control the film transporting device, the exposing device, the heat developing device and the density measuring device;

wherein the testing exposure data comprise first test data to form a first test image on at least one of a leading edge portion and a trailing edge portion of a film,

the exposing device forms a latent image of the first test image based on the first test data,

the heat developing device visualizes the first test image,

the density measuring device measures the density of the first test image on the film and

the controlling device determines a correction area on the at least one of the leading edge portion and the trailing edge portion of the film based on the result of the density measurement of the first test image and corrects the density characteristic of an area of another film corresponding to the determined correction area when a medical image is recorded on the another film based on diagnostic image data, and

wherein the testing exposure data further includes another test data to form another test image for correction of a whole area of the film.