To provide a hollow yarn membrane module large in water permeation quantity and excellent in durability.

A microporous layer having reinforcing function is laminated on a microporous layer having separation function and the wall surfaces of micropores are coated with a hydrophilic copolymer, and polyolefin composite microporous hollow yarn membranes 3 each having at least two microporous layers different in pore size are fixed and arranged within a cylindrical structure 1.