A traffic cone having an alarm function is provided. The traffic cone is configured to blow an air horn by opening an air flow valve when an external impact occurs so that workers can escape a dangerous situation quickly, and to be mounted easily and conveniently to an existing traffic cone without any separate manufacturing process. Further, the traffic cone improves price competitiveness by reducing processes and costs with recyclable components, prevents environmental contamination, applies simplified structures, and improves precision, thereby greatly enhancing convenience and the product life.