A method of pre-peeling a double container

Provided is a pre-peeling method for a double container, which can perform pre-peeling while suppressing damage to an inner bag. According to the present invention, there is provided a pre-peeling method for a double container having an outer shell and an inner bag, the method comprising: A peeling step of peeling the inner bag from the outer shell by breaking a bite portion provided on a bottom portion of the outer shell in a state where an inner pressure of the inner bag is negative, Methods are provided. In the peeling step, the cutting part may be broken by applying a force to a portion of the bottom portion that is displaced from the cutting part. The method may further comprise an inspection step, and the inspection step may inspect whether or not a pin hole exists in the inner bag based on data obtained when the inside of the...