The present invention pertains to a polyolefin-composite hollow-fiber membrane and a manufacturing method for the same, said polyolefin-composite hollow-fiber membrane having: a homogenous membrane layer formed from polyolefins having a metal flow rate measured in accordance with JIS K7210 code D of 1.0 g/10 minutes, or less, and an Mw/Mn ratio of not more than 4.0; and a porous membrane layer which is formed from polyolefins having an Mw/Mn ratio of 8.0-12.0. The present invention also pertains to a hollow-fiber membrane module which is equipped with the polyolefin-composite hollow-fiber membrane. The present invention enables the provision of a polyolefin-composite hollow-fiber membrane, a manufacturing method for the same and a hollow-fiber membrane module; the polyolefin-composite hollow-fiber membrane has excellent solvent resistance and gas permeability, and when used in the deaeration of dissolved gas in a drug solution, can suppress leakage of the drug solution to a high degree, and can efficiently reduce the amount of dissolved gas.