Recently ultrasonic activated scalpel(Harmonic scalpel)has become an important tool in laparoscopic surgery. We measured the number of air particulate under using Harmonic scalpel and examined the droplet spread of vial bacteria. The number of air particulate around the operator's face, was elevated by using Harmonic scalpel as same as electrical knife. The droplet spread of vial bacteria by using Harmonic scalpel were much more than electrical knife. Harmonic scalpel has a demerit of droplet spread. We must be careful to use Harmonic scalpel and know the risk of exposure to air particle.