  The flux creep problem for a superconductor slab placed in a constant or
time-dependent magnetic field is considered. Logarithmic dependence of the
activation energy on the current density is assumed, U=U0 ln(J/Jc), with a
field dependent Jc. The density B of the magnetic flux penetrating into the
superconductor, is shown to obey a scaling law, i.e., the profiles B(x) at
different times can be scaled to a function of a single variable. We found
exact solution for the scaling function in some specific cases, and an
approximate solution for a general case. The scaling also holds for a slab
carrying transport current I resulting in a power-law V(I) with exponent p~1.
When the flux fronts moving from two sides of the slab collapse at the center,
the scaling is broken and p crosses over to U0/kT.
