To contrive time reduction by rationalizing the process for changing the top roll of a squeezing roll stand in an electric resistance welded tube manufacturing line and performing the operation rapidly and exactly.

A top roll changing device is used which is provided with a lifting frame 30 provided with a horizontal pin 32, an overturning device 40 having a slope for receiving an inclining a lifted assembly 10, a locking piece 14 for inclining the assembly 10 by locking at the upper end of the slope, a stopper 42 which is the center of revolution for further overturning and holding bases 42, 44 for holding the assembly 10 which is overturned and rolled sideways.