  We formulate a theory for N=4 supersymmetric Yang-Mills multiplet in a
non-adjoint representation R of SO(N) as an important application of our
recently-proposed model for N=1 supersymmetry. This system is obtained by
dimensional reduction from an N=1 supersymmetric Yang-Mills multiplet in
non-adjoint representation in ten dimensions. The consistency with
supersymmetry requires that the non-adjoint representation R with the indices
i, j, ... satisfy the three conditions \eta^{i j} = \delta^{i j}, (T^I)^{i j} =
- (T^I)^{j i} and (T^I)^{[ i j |} (T^I)^{| k ] l} = 0 for the metric \eta^{i j}
and the generators T^I, which are the same as the N=1 case.
