A multicolor image-forming material comprising: an image-receiving sheet comprising a support and an image-receiving layer; and at least four thermal transfer sheets each comprising a support, a light-to-heat converting layer and an image-forming layer, and each having a different color, wherein an image is formed by the method comprising the steps of: superposing each one of the at least four thermal transfer sheets on the image-receiving sheet to be in a state of the image-forming layer being in contact with the image-receiving layer; and irradiating the thermal transfer sheet with a laser beam to transfer an image in an area of the image-forming layer subjected to irradiation onto the image-receiving layer, the image-receiving sheet has both lengthwise and breadthwise lengths of 50 cm or more, and an area (length x breadth) of 3,000cm 2 or more, and a spectral reflectance of a surface of the image-receiving layer to the laser beam is 65% or more.