A process belt for papermaking with a long operational life including an integrated structure of a reinforcing fibrous base material and a polyurethane layer is disclosed. The reinforcing fibrous base material is embedded in the polyurethane and the outer peripheral surface and the inner peripheral surface are made of the polyurethane. Nanoparticles including, as a 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.