A porous hollow-fiber membrane comprising a fluororesin-based polymer, wherein the porous hollow-fiber membrane has a columnar texture oriented in a longitudinal direction thereof, a molecular chain in the columnar texture is oriented in the longitudinal direction of the porous hollow-fiber membrane, and the molecular chain has an average value v of a Raman orientation parameter being from 1.5 to 3.0, wherein said Raman orientation parameter is determined as set out in the description, - wherein the fluororesin-based polymer is a vinylidene fluoride homopolymer, and/or a copolymer of vinylidene fluoride monomer and one or more kinds of monomers selected from vinyl fluoride, tetrafluoroethylene, hexafluoropropylene and chlorotrifluoroethylene, - wherein the porous hollow-fiber membrane has a porosity being from 40 to 80%, - wherein a proportion of the columnar texture in the porous hollow-fiber membrane in a cross section of longitudinal direction is 80 wt% or more, - wherein the columnar texture has a longitudinal length of 7 μm or more and 50 μm or less, a short-side length of from 0.5 to 3 μm and an aspect ratio of 3 or more, - wherein the porous hollow-fiber membrane has a columnar texture having a thickness uniformity of 0.50 or more and less than 1.00 oriented in a longitudinal direction thereof, - and the molecular chain of the fluororesin-based polymer has an orientation degree n in the longitudinal direction of the porous hollow-fiber membrane being less than 0.4, or the molecular chain of the fluororesin-based polymer is non-oriented, - wherein the molecular chain in the columnar texture has a ratio M/m of a maximum Raman orientation parameter M to a minimum Raman orientation parameter m being from 1.5 to 4.0 - and a maximum Raman orientation parameter M of the molecular chain in the columnar texture being 4.0 or less, wherein all parameters are determined as detailed in the specification. wherein the porous hollow-fiber membrane has a columnar texture oriented in a longitudinal direction thereof, a molecular chain in the columnar texture is oriented in the longitudinal direction of the porous hollow-fiber membrane, and the molecular chain has an average value v of a Raman orientation parameter being from 1.5 to 3.0, wherein said Raman orientation parameter is determined as set out in the description, - wherein the fluororesin-based polymer is a vinylidene fluoride homopolymer, and/or a copolymer of vinylidene fluoride monomer and one or more kinds of monomers selected from vinyl fluoride, tetrafluoroethylene, hexafluoropropylene and chlorotrifluoroethylene, - wherein the porous hollow-fiber membrane has a porosity being from 40 to 80%, - wherein a proportion of the columnar texture in the porous hollow-fiber membrane in a cross section of longitudinal direction is 80 wt% or more, - wherein the columnar texture has a longitudinal length of 7 μm or more and 50 μm or less, a short-side length of from 0.5 to 3 μm and an aspect ratio of 3 or more, - wherein the porous hollow-fiber membrane has a columnar texture having a thickness uniformity of 0.50 or more and less than 1.00 oriented in a longitudinal direction thereof, - and the molecular chain of the fluororesin-based polymer has an orientation degree n in the longitudinal direction of the porous hollow-fiber membrane being less than 0.4, or the molecular chain of the fluororesin-based polymer is non-oriented, - wherein the molecular chain in the columnar texture has a ratio M/m of a maximum Raman orientation parameter M to a minimum Raman orientation parameter m being from 1.5 to 4.0 - and a maximum Raman orientation parameter M of the molecular chain in the columnar texture being 4.0 or less, - wherein the fluororesin-based polymer is a vinylidene fluoride homopolymer, and/or a copolymer of vinylidene fluoride monomer and one or more kinds of monomers selected from vinyl fluoride, tetrafluoroethylene, hexafluoropropylene and chlorotrifluoroethylene, - wherein the porous hollow-fiber membrane has a porosity being from 40 to 80%, - wherein a proportion of the columnar texture in the porous hollow-fiber membrane in a cross section of longitudinal direction is 80 wt% or more, - wherein the columnar texture has a longitudinal length of 7 μm or more and 50 μm or less, a short-side length of from 0.5 to 3 μm and an aspect ratio of 3 or more, - wherein the porous hollow-fiber membrane has a columnar texture having a thickness uniformity of 0.50 or more and less than 1.00 oriented in a longitudinal direction thereof, - and the molecular chain of the fluororesin-based polymer has an orientation degree n in the longitudinal direction of the porous hollow-fiber membrane being less than 0.4, or the molecular chain of the fluororesin-based polymer is non-oriented, - wherein the molecular chain in the columnar texture has a ratio M/m of a maximum Raman orientation parameter M to a minimum Raman orientation parameter m being from 1.5 to 4.0 - and a maximum Raman orientation parameter M of the molecular chain in the columnar texture being 4.0 or less, wherein all parameters are determined as detailed in the specification.