A hollow fiber membrane module is disclosed, which is capable of preventing a bundle of hollow fiber membranes from being separated from a module case, the hollow fiber membrane module for accommodating a bundle of hollow fiber membranes closely held together through the use of potting agent, including a module case including: a first inner surface serving as a projection on which the bundle of hollow fiber membranes is stably placed; a second inner surface upwardly extending from one end of the first inner surface, the second inner surface including at least one separation-preventing groove to prevent the bundle of hollow fiber membranes from being separated from the module case; a third inner surface downwardly extending from the other end of the first inner surface; and a fourth inner surface connected to the third inner surface.