To obtain a crown roller device which enables adaptation to base films with various thicknesses.

In a crown roller device 10, for example, a roll body 20 of crown rollers which are set on the outlet side of an air floating drier 1 for drying a magnetic paint applied on a base film F and act to extend the base film F slackened by a thermal distortion is swelled by an air pressure. An elastic cylinder 22 is arranged and a metal coil 23 is wound on the surface thereof to make the radius of curvature variable.