A gas component measuring device comprising: a cyclone that has a gas inlet; and a laser gas analyzer configured to take, in the cyclone, a measurement of a component of a subject gas that contains particulate matter and is introduced into the cyclone through the gas inlet, wherein: the cyclone has a pair of opening portions (26a, 26b), opposed to each other, in a side surface thereof; a light emitting portion of the laser gas analyzer is disposed so as to emit laser light into the cyclone through one of the pair of opening portions (26a, 26b), and a light receiving portion of the laser gas analyzer is disposed so as to receive the laser light that exits through the other of the pair of opening portions (26a, 26b); and the gas component measuring device further includes a displacing device configured to reduce the particulate matter on an optical path of the laser light by hindering passage of the particulate matter in a vicinity of each of the pair of opening portions (26a, 26b) within the cyclone, wherein the displacing device includes a gas injection device configured to inject purge gas inward through each of the pair of opening portions (26a, 26b), and/or the displacing device includes a hollow pipe provided so as to protrude inward from each of the pair of opening portions (26a, 26b). a cyclone that has a gas inlet; and a laser gas analyzer configured to take, in the cyclone, a measurement of a component of a subject gas that contains particulate matter and is introduced into the cyclone through the gas inlet, wherein: the cyclone has a pair of opening portions (26a, 26b), opposed to each other, in a side surface thereof; a light emitting portion of the laser gas analyzer is disposed so as to emit laser light into the cyclone through one of the pair of opening portions (26a, 26b), and a light receiving portion of the laser gas analyzer is disposed so as to receive the laser light that exits through the other of the pair of opening portions (26a, 26b); and the gas component measuring device further includes a displacing device configured to reduce the particulate matter on an optical path of the laser light by hindering passage of the particulate matter in a vicinity of each of the pair of opening portions (26a, 26b) within the cyclone, wherein the displacing device includes a gas injection device configured to inject purge gas inward through each of the pair of opening portions (26a, 26b), and/or the displacing device includes a hollow pipe provided so as to protrude inward from each of the pair of opening portions (26a, 26b). the cyclone has a pair of opening portions (26a, 26b), opposed to each other, in a side surface thereof; a light emitting portion of the laser gas analyzer is disposed so as to emit laser light into the cyclone through one of the pair of opening portions (26a, 26b), and a light receiving portion of the laser gas analyzer is disposed so as to receive the laser light that exits through the other of the pair of opening portions (26a, 26b); and the gas component measuring device further includes a displacing device configured to reduce the particulate matter on an optical path of the laser light by hindering passage of the particulate matter in a vicinity of each of the pair of opening portions (26a, 26b) within the cyclone, wherein the displacing device includes a gas injection device configured to inject purge gas inward through each of the pair of opening portions (26a, 26b), and/or the displacing device includes a hollow pipe provided so as to protrude inward from each of the pair of opening portions (26a, 26b).