A conveyor belt includes a plurality of modules arranged in succession and articulated with each other. First and second projections of the modules have mating profiles to allow the insertion of a connecting pin between adjacent modules. Each module includes housings for respective rolling balls projecting through a respective circular opening. The ratio between the diameter of at least one circumferential portion of the housing and the diameter of the respective rolling ball is between 0.8 and 0.6, while at least part of a rib is provided below, near the lower surface, with at least one respective projecting portion arranged for snap-fit insertion of the rolling ball into the respective housing seat.