To prepare a liquid separation membrane hard to cause fouling when a suspended substance relatively large in particle size is removed, easily to peel fouling even if fouling is caused and having high durability.

In the liquid separation membrane for subjecting a raw liquid to separation to obtain a filtrate, the average value X of the distances between the adjacent apexes of the surface on the raw liquid side having unevenness in a certain cross section of the liquid separation membrane and the average value Z of the unevenness differences between the mutually adjacent apexes and base points of the surface on the raw liquid side satisfy the relations: 0.01 μm≤X≤10 μm and Z/X≥0.5.