Disclosed is a clad material for an LED light-emitting element holding substrate in which a plurality of layers composed of different materials are stacked and bonded via a metal layer to a III-V group semiconductor crystal surface, the linear expansion coefficient being 14×10−6/K or less and the thermal conductivity at a temperature of 25° C. being 200 W/mK or greater. The clad material is composed of three alternately stacked layers: two copper layers and a molybdenum layer, the molybdenum layer being 10 to 60 vol % and the difference in thickness between the copper layers being 5% or less; or a clad material composed of three copper layers alternately stacked with molybdenum layers to make five layers, the molybdenum layers being 20 to 70 vol % and the difference in thickness between the top and bottom two copper layers and the molybdenum layers being 5% or less.