There is provided a technique of reducing the possibility of the occurrence of wrinkles in the process of bonding strip-shaped members to each other. A long strip-shaped first member is conveyed in a longitudinal direction of the first member. A width of a long strip-shaped second member in the shorter direction of the second member is larger than a width of the first member in a shorter direction of the first member. The second member is placed such that respective ends in a shorter direction of the second member are freed. The second member is bonded to the first member being conveyed, such that the shorter direction of the first member is aligned with the shorter direction of the second member and that respective ends in the shorter direction of the first member are placed between the respective ends in the shorter direction of the second member. The second member bonded to the first member is then conveyed along with the conveyed first member.