A liquid separation membrane module includes a semipermeable membrane receiving a pressure of a feed liquid, and a channel material arranged so as to support the back side of the semipermeable membrane. The channel material is a tricot knitted fabric knitted by a tricot knitting machine with two reeds and has a ground stitch portion and a convex portion. The tricot knitted fabric includes a thermoplastic synthetic filament yarn with a core/sheath type conjugated fiber having a high melting point polymer as a core component and a low melting point polymer as a sheath component. Thermoplastic synthetic filament yarns for forming the ground stitch portion and the convex portion have a substantially same fineness, and the yarns in the tricot knitted fabric are bonded with one another by melt adhesion of the low melting point component to rigidity the entire knitted fabric.