The present invention addresses the problem of providing a composite nanometal paste which is relatively low in price and is excellent in terms of bonding characteristics, thermal conductivity, and electrical property.The present invention is a copper-filler-containing composite nanometal paste that contains composite nanometal particles each comprising a metal core and an organic coating layer formed thereon. The metal paste contains a copper filler and contains, as binders, first composite nanometal particles and second composite nanometal particles which differ from the first composite nanometal particles in the thermal decomposition temperature of the organic coating layer, wherein the mass proportion W1 of the organic coating layer in the first composite nanometal particles is in the range of 2-13 mass %, the mass proportion W2 of the organic coating layer in the second composite nanometal particles is in the range of 5-25 mass %, and these particles satisfy the relationships W1.