An apparatus configured to inspect responsivity of a gas sensor, said apparatus comprising: a chamber, a gas supply source configured to generate gas for inspection, and a gas exhaust part through which the gas for inspection having passed through the chamber is exhausted, the chamber including a plurality of up to 10 inspection pipe units, each include a cylindrical gas flowing part having an identical diameter and each comprising an inspected sensor disposing part, wherein the inspection pipe units are joined with each other from the upstream side so that the respective gas flowing parts are coaxially disposed forming one gas flow path which represents the x-axis in a positive direction in a right-handed xyz coordinate system; the plurality of inspected sensor disposing parts that are provided extend vertically upward in a positive z-axis direction and are provided halfway through said one gas flow path at equal intervals in an extending direction of said one gas flow path and in each of which a gas sensor to be inspected is disposed; and a plurality of straightening plates provided on positions upstream of each of said inspected sensor disposing parts on said one gas flow path, each of said positions separated at a constant distance from the corresponding inspected sensor disposing parts, wherein: said straightening plates each include a rectangular opening orthogonal to said one gas flow path and open to said one gas flow path, the width (w) of the opening, which is the size in the γ-axis direction, is set to be same as the diameter of the gas flowing part, and the height (h) of the opening, which is the size in the z-axis direction, is set to be smaller than the width (w), and said apparatus is configured and arranged so that responsivity of said gas sensor is inspected by causing the gas for inspection to flow through said one gas flow path when said gas sensor to be inspected is disposed at each of said inspected sensor disposing parts. a chamber, a gas supply source configured to generate gas for inspection, and a gas exhaust part through which the gas for inspection having passed through the chamber is exhausted, the chamber including a plurality of up to 10 inspection pipe units, each include a cylindrical gas flowing part having an identical diameter and each comprising an inspected sensor disposing part, wherein the inspection pipe units are joined with each other from the upstream side so that the respective gas flowing parts are coaxially disposed forming one gas flow path which represents the x-axis in a positive direction in a right-handed xyz coordinate system; the plurality of inspected sensor disposing parts that are provided extend vertically upward in a positive z-axis direction and are provided halfway through said one gas flow path at equal intervals in an extending direction of said one gas flow path and in each of which a gas sensor to be inspected is disposed; and a plurality of straightening plates provided on positions upstream of each of said inspected sensor disposing parts on said one gas flow path, each of said positions separated at a constant distance from the corresponding inspected sensor disposing parts, wherein: said straightening plates each include a rectangular opening orthogonal to said one gas flow path and open to said one gas flow path, the width (w) of the opening, which is the size in the γ-axis direction, is set to be same as the diameter of the gas flowing part, and the height (h) of the opening, which is the size in the z-axis direction, is set to be smaller than the width (w), and said apparatus is configured and arranged so that responsivity of said gas sensor is inspected by causing the gas for inspection to flow through said one gas flow path when said gas sensor to be inspected is disposed at each of said inspected sensor disposing parts. said straightening plates each include a rectangular opening orthogonal to said one gas flow path and open to said one gas flow path, the width (w) of the opening, which is the size in the γ-axis direction, is set to be same as the diameter of the gas flowing part, and the height (h) of the opening, which is the size in the z-axis direction, is set to be smaller than the width (w), and said apparatus is configured and arranged so that responsivity of said gas sensor is inspected by causing the gas for inspection to flow through said one gas flow path when said gas sensor to be inspected is disposed at each of said inspected sensor disposing parts.