  We show a possibility that a color ferromagnetic state exists in SU(3) gauge
theory of quark matter with two flavors. Although the state involves three
types of unstable modes of gluons, all of these modes are stabilized by forming
a quantum Hall state of one of the modes. We also show that at large chemical
potential, a color superconducting state (2SC) appears even in the
ferromagnetic state. This is because Meissner effect by condensed anti-triplet
quark pairs does not work on the magnetic field in the ferromagnetic state.

High Energy Physics - Phenomenology