PURPOSE: To form a three-dimensional object by a method wherein after a part of a photohardenable liq. layer with a specified compsn. is cured by irradiating it with an active radiation, a new photohardenable liq. layer is additionally laminated and this laminate is irradiated with the active radiation.

CONSTITUTION: An ethylenic unsatd. monomer, a photoinitiator and a radiation deflecting matter are compounded and a photohardenable liq. layer wherein the radiation deflecting matter has the first refractive index and the remaining part has the second refractive index and the absolute value of the difference in the first and the second refractive indices is at least O is formed. After this photohardenable liq. layer is irradiated with an active radiation and at least part of the layer is cured, a new layer of the photohardenable liq. is provided on this layer. Then, the new layer is irradiated with the active radiation to integrate them by curing at least a part of the layer and an integral three- dimensional object is thereby formed.