Laminate, the method of separating the laminate, and evaluation method of separating layer

Laminate (1) includes a substrate (11), an adhesive layer (14), the separation layer to deterioration by absorbing light (16), support plate (12) and are stacked in this order, the optical density of the separation layer 16 0.2 or more and 1.0 or less. The invention also includes a method of separating the laminated body 1 including the step of evaluating the optical density of the separation layer (16), and the evaluation method of the separating layer.