The invention relates to a carbon dioxide generator. The carbon dioxide generator is an electrolyzer with a sealing cap; a positive electrode plate and a negative electrode plate are arranged inside the electrolyzer; the electrode plates are platinized titanium meshes; the distance between the positive electrode plate and the negative electrode plate is 3-7 mm; the electrode plates are connected with a DC power supply nonpolar wiring female plug. The invention also provides a mosquito killing device comprising the carbon dioxide generator and application of the mosquito killing device. Under the same conditions, the mosquito killing device provided by the invention is larger in carbon dioxide generation amount and higher in mosquito guiding capability, so that the mosquito killing efficiency is higher, and the cost is reduced; as a DC nonpolar power supply is adopted, the use is more convenient and safer; a self-suction and self-discharge pump is mounted, so that the addition of an electrolyte solution and the cleaning of the electrolyzer are more convenient and smoother, and the working efficiency of working personnel or users is improved.