  We present the first implementation of the Cho--Faddeev--Niemi decomposition
of the SU(2) Yang-Mills field on a lattice. Our construction retains the color
symmetry (global SU(2) gauge invariance) even after a new type of Maximally
Abelian gauge, as explicitly demonstrated by numerical simulations. Moreover,
we propose a gauge-invariant definition of the magnetic monopole current using
this formulation and compare the new definition with the conventional one by
DeGrand and Toussaint to exhibit its validity.
