  We introduce a Dirac equation which reproduces the usual radial sextic
oscillator potential in the non-relativistic limit. We determine its energy
spectrum in the presence of the magnetic field. It is shown that the equation
is solved in the context of quasi-exactly-solvable problems. The equation
possesses hidden $sl_{2}$-algebra and the destroyed symmetry of the equation
can be recovered for a specific values of the magnetic field which leads to
exact determination of the eigenvalues.
