To provide a paper tube manufacturing device, capable of manufacturing two paper tubes, or two types of paper tubes by one device at the same time and to provide the method.

One center base cylinder 6 is arranged between right and left mandrels 3a, 3b, and external base cylinders 7a, 7b, 8b are arranged on both sides of each mandrel 3a, 3b. Endless belts 9a, 9b, 10a, 10b that are wound around each mandrel 3a, 3b, are spanned between the center base cylinder 6 and each of the right and left base cylinders 7a, 7b, 8a, 8b. Driving the center base cylinder 6 allows the endless belts to revolve simultaneously to produce two paper tubes at the same time.