  We consider the global solvability to the Cauchy problem of Kirchhoff
equation with generalized classes of Manfrin's class. Manfrin's class is a
subclass of Sobolev space, but we shall extend this class as a subclass of the
ultradifferentiable class, and we succeed to prove the global solvability of
Kirchhoff equation with large data in wider classes from the previous works.
