A process belt for papermaking with a long operational life comprises an integrated structure of a reinforcing fibrous base material 6 and a polyurethane layer. The reinforcing fibrous base material is embedded in the polyurethane and the outer peripheral surface 21 and the inner peripheral surface 22 are made of the polyurethane. Nanoparticles comprising, as main component, a silicon oxide component, the surface of which is treated with an organic silane coupling agent, are homogeneously dispersed in one part or all of the polyurethane.