An optical device, comprising: first and second outer substrates (101, 102) disposed so as to face each other; an active liquid crystal film layer; wherein the active liquid crystal film layer is encapsulated by an encapsulating agent between the first and second outer substrates (101, 102), wherein the active liquid crystal film layer comprises: two base film layers (201, 202) disposed so as to face each other; and a liquid crystal material in a gap between the base film layers (201, 202), characterized in that the optical device further comprises a step forming layer encapsulated together with the active liquid crystal film layer by the encapsulating agent between the first and second outer substrates (101, 102), in that the active liquid crystal film layer comprises a region that is depressed by the step forming layer and a region that is not depressed by the step forming layer, in that a size of the gap between the two base film layers (201, 202) facing each other in the region, which is depressed by the step forming layer, of the active liquid crystal film layer is different from a size of the gap between the two base film layers (201, 202) facing each other in the region, which is not depressed by the step forming layer, of the active liquid crystal film layer, and in that a ratio of the size G1 of the gap in the region depressed by the step forming layer with respect to the size G2 of the gap in the region that is not depressed by the step forming layer is from 10% to 95%. first and second outer substrates (101, 102) disposed so as to face each other; an active liquid crystal film layer; wherein the active liquid crystal film layer is encapsulated by an encapsulating agent between the first and second outer substrates (101, 102), wherein the active liquid crystal film layer comprises: two base film layers (201, 202) disposed so as to face each other; and a liquid crystal material in a gap between the base film layers (201, 202), characterized in that the optical device further comprises a step forming layer encapsulated together with the active liquid crystal film layer by the encapsulating agent between the first and second outer substrates (101, 102), in that the active liquid crystal film layer comprises a region that is depressed by the step forming layer and a region that is not depressed by the step forming layer, in that a size of the gap between the two base film layers (201, 202) facing each other in the region, which is depressed by the step forming layer, of the active liquid crystal film layer is different from a size of the gap between the two base film layers (201, 202) facing each other in the region, which is not depressed by the step forming layer, of the active liquid crystal film layer, and in that a ratio of the size G1 of the gap in the region depressed by the step forming layer with respect to the size G2 of the gap in the region that is not depressed by the step forming layer is from 10% to 95%. two base film layers (201, 202) disposed so as to face each other; and a liquid crystal material in a gap between the base film layers (201, 202), characterized in that the optical device further comprises a step forming layer encapsulated together with the active liquid crystal film layer by the encapsulating agent between the first and second outer substrates (101, 102), in that the active liquid crystal film layer comprises a region that is depressed by the step forming layer and a region that is not depressed by the step forming layer, in that a size of the gap between the two base film layers (201, 202) facing each other in the region, which is depressed by the step forming layer, of the active liquid crystal film layer is different from a size of the gap between the two base film layers (201, 202) facing each other in the region, which is not depressed by the step forming layer, of the active liquid crystal film layer, and in that a ratio of the size G1 of the gap in the region depressed by the step forming layer with respect to the size G2 of the gap in the region that is not depressed by the step forming layer is from 10% to 95%.