We previously presented a FCP model that showed good fit with a wide range of actual performance data on a hollow fiber reverse osmosis module. However, this analytical model contained the anomaly that the simulated boundary layer thickness is larger than the apparent length of the clearance among hollow fibers. Here, we propose a hollow fiber faggot model that is consistent with the features of the hollow fiber arrangement of the practical reverse osmosis module. As a result of verifying this model, it was confirmed that the boundary layer thickness on the surface of the faggot is smaller than the length of clearance between the faggots of hollow fibers.