An airflow speed detection device for measuring an airflow speed includes an airflow speed switch, and a connector. The airflow speed switch includes a detection head, and an elastic piece. The connector is electrically connected to the testing the airflow speed switch to connect an indicator to indicate close and open states of the airflow speed switch. If the airflow speed is not faster than a critical value, the elastic piece contacts the detection head to close the airflow speed switch. If the airflow speed is faster than the critical value, the elastic piece is blown away from the detection head to open the airflow speed switch.