To provide a laminate device capable of omitting an advanced tension adjustment process while securing simplification of the device and a control system.

A laminate device contains a nip roll 2 for crimping a film F onto a carried flat body G, a film roll 3 for providing the nip roll 2 to the film F, a guide roll 4 for guiding the rolled out film F from the film roll 3 to the nip roll 2, tension adding means 5 for keeping tension of the film F supplied to the nip roll 2 constant, and the tension adding means 5 contains tension detection means 51 for detecting tension of the film F supplied to the nip roll 2 and tension control means 52 for controlling a peripheral speed of the film roll 3 to have a constant speed difference Δv with respect to a peripheral speed of the nip roll 2 based on an output value of the tension detection means 51.