  Magnetic susceptibility of the quark matter in QCD is calculated in a closed
form for an arbitrary chemical potential \mu. For small \mu, \mu<<T, eB << T^2,
a strong dependence on temperature T is found due to Polyakov line factors. In
the opposite case of small T, eB > T^2, the oscillations as functions of eB
occur, characteristic of the de Haas-van Alphen effect. Results are compared
with available lattice data.
