A discharge ionization current detector capable of supplying plasma gas in large quantity to stabilize plasma simultaneously with lowering the sample dilution ratio to improve detection sensitivity is provided. A gas supply pipe 7 for supplying a plasma gas, which also functions as a dilution gas, is connected to a point near the connecting section of a first gas passage 3 having electrodes 4-6 for plasma generation and a second gas passage having electrodes 16 and 17 for ion detection. A first gas discharge pipe 8 is connected to the other end of the first gas passage 3, and a second gas discharge pipe 13 is connected to the other end of the second gas passage 11. Flow controllers 9 and 14 are provided in the gas discharge pipes 8 and 13, respectively. The flow rate of the gas passing through a plasma generation area and that of the gas passing through an ion current detection area can be independently regulated. Therefore, for example, it is possible to increase the former flow rate to stabilize the plasma and simultaneously decrease the latter flow rate to enhance the detection sensitivity for a low-concentration sample.