  The q-state Potts field theory with $2\le q\le 4$ in the low-temperature
phase is considered in presence of a weak magnetic field h. In absence of the
magnetic field, the theory is integrable, but not free at q>2: its elementary
excitations - the kinks - interact at small distances, and their interaction
can be characterized by the factorizable scattering matrix which was found by
Chim and Zamolodchikov. The magnetic field induces the long-range attraction
between kinks causing their confinement into the bound-states. We calculate the
masses of the two-kink bound states in the leading order in |h| -> 0 expressing
them in terms of the scattering matrix of kinks at h=0.
