The superconducting gap structure, especially the direction of the nodes, is an unresolved issue in most of unconventional superconductors. Here, we have measured the thermal conductivity of 2D unconventional superconductors, spin-triplet Sr2RuO4 and heavy fermion CeCoIn5, in magnetic field rotating within the planes. On the basis of the angular variation of the thermal conductivity, we demonstrate that the gap function of Sr2RuO4 is d(k) = Delta(0)(z) over cap (k(x) + ik(y)) (cos ck(2) + alpha), and the gap function of CeCoIn5 is d(x2-y2). (C) 2002 Elsevier Science B.V. All rights reserved.