  We consider topological Hall effect (THE) in thin ferromagnetic films due to
electron scattering on magnetic skyrmions in the presence of the relatively
strong external magnetic field. We account for the effect of the magnetic field
on a skyrmion structure and describe the hallmarks of THE differentiating it
from ordinary and anomalous Hall effects. We have found that, although in
typical ferromagnets the variation of magnetic field in the range 1-5 T
substantially affects the skyrmion size, THE changes rather weakly remaining
quite robust. Therefore, the magnitude of THE is primarily determined by the
skyrmions sheet density $n_{sk}$, being comparable to the magnitude of the
ordinary Hall effect (OHE) at $n_{sk}=10^{11}$ cm$^{-2}$. The sign of THE is
opposite to that of OHE for skyrmions with positive vorticity, while for
antiskyrmions the signs are the same.
