A false roller device with variable roller spacing for an eleven-roller metal plate and band straightener belongs to the technical field of metal plate and band straighteners. The false roller device with variable roller spacing is prepared based on the eleven-roller metal plate and band straightener in the prior art, namely straightening rollers (3, 4, 6, 7, 9 and 10) are removed from the eleven-roller straightener, straightening rollers (1, 2, 5, 8 and 11) are kept, and an idle roller head (14) connected with a transmission mechanism is arranged in the primary bearing without the straightening rollers (3, 4, 6, 7, 9 and 10). The false roller device has the advantages of increasing the functions and functions of the eleven-roller metal plate and band straightener, meeting the production requirement conveniently and saving equipment investment.