A total organic carbon measuring device comprising: a syringe pump configured to collect sample water; an oxidation reaction unit including a combustion tube configured to oxidatively decompose and convert into carbon dioxide carbon components in the sample water collected by the syringe pump, and a heating furnace configured to heat the combustion tube; a measurement unit including a sample cell, connected to an outlet portion of the combustion tube, the sample cell configured to cause sample gas containing carbon dioxide generated in the combustion tube to flow through, and a detector configured to measure carbon dioxide concentration in the sample gas flowing through the sample cell; a carrier gas supply unit including a carrier gas introduction path configured to introduce a carrier gas, a first supply path having one end connected to a downstream end of the carrier gas introduction path and the other end connected in a manner capable of communicating with the syringe pump, a second supply path, different from the first supply path, having one end connected to the downstream end of the carrier gas introduction path and the other end connected to the combustion tube, a first flow rate adjustment mechanism configured to adjust a flow rate of the carrier gas flowing through the first supply path, and a second flow rate adjustment mechanism configured to adjust, independently from the first flow rate adjustment mechanism, a flow rate of the carrier gas flowing through the second supply path; a bypass path being connected to a path between the combustion tube and the sample cell; a path switching mechanism configured to switch between a sparging state and a normal state, the sparging state communicating the other end of the first supply path with a drain through the syringe pump, and the normal state communicating the other end of the first supply path to the sample cell through the bypass path; and a flow rate control unit configured to control the first flow rate adjustment mechanism and the second flow rate adjustment mechanism in such a way that the carrier gas flows through the first supply path and the second supply path at a predetermined flow rate, the flow rate control unit including cell flow rate control means configured to control the first flow rate adjustment mechanism and the second flow rate adjustment mechanism so that a flow rate of the carrier gas introduced into the sample cell through the second supply path in the sparging state and a flow rate of the carrier gas introduced into the sample cell through both the first and second supply paths (56, 57) in the normal state become the same. a syringe pump configured to collect sample water; an oxidation reaction unit including a combustion tube configured to oxidatively decompose and convert into carbon dioxide carbon components in the sample water collected by the syringe pump, and a heating furnace configured to heat the combustion tube; a measurement unit including a sample cell, connected to an outlet portion of the combustion tube, the sample cell configured to cause sample gas containing carbon dioxide generated in the combustion tube to flow through, and a detector configured to measure carbon dioxide concentration in the sample gas flowing through the sample cell; a carrier gas supply unit including a carrier gas introduction path configured to introduce a carrier gas, a first supply path having one end connected to a downstream end of the carrier gas introduction path and the other end connected in a manner capable of communicating with the syringe pump, a second supply path, different from the first supply path, having one end connected to the downstream end of the carrier gas introduction path and the other end connected to the combustion tube, a first flow rate adjustment mechanism configured to adjust a flow rate of the carrier gas flowing through the first supply path, and a second flow rate adjustment mechanism configured to adjust, independently from the first flow rate adjustment mechanism, a flow rate of the carrier gas flowing through the second supply path; a bypass path being connected to a path between the combustion tube and the sample cell; a path switching mechanism configured to switch between a sparging state and a normal state, the sparging state communicating the other end of the first supply path with a drain through the syringe pump, and the normal state communicating the other end of the first supply path to the sample cell through the bypass path; and a flow rate control unit configured to control the first flow rate adjustment mechanism and the second flow rate adjustment mechanism in such a way that the carrier gas flows through the first supply path and the second supply path at a predetermined flow rate, the flow rate control unit including cell flow rate control means configured to control the first flow rate adjustment mechanism and the second flow rate adjustment mechanism so that a flow rate of the carrier gas introduced into the sample cell through the second supply path in the sparging state and a flow rate of the carrier gas introduced into the sample cell through both the first and second supply paths (56, 57) in the normal state become the same.