We evaluated the differences in instrument manipulation skills between expert laparoscopic surgeons and novices.Six expert surgeons who had performed more than 500 laparoscopic surgeries and one skilled instructor at Kyushu University Training Center for Minimally Invasive Surgery, and 20 medical students who had experienced no laparoscopic surgery were enrolled. A new skill assessment task was designed using zippers on an unstable, mobile platform in a box trainer. The examinees were asked to close the zippers, while trying to avoid moving the platform. The path lengths of the tips of the instruments and of the platform were measured, and the performance time was also recorded. Surgical skill score was calculated from the correlation between the path lengths of the instruments and that of the platform, in addition to the performance time.The path lengths of the tips of both instruments and of the platform were significantly shorter in the experts than in the novices (all p < 0.05). The performance time was also significantly shorter for experts than novices (p < 0.05). The surgical skill score was significantly higher for experts than novices (p < 0.01).The differences in the instrument manipulation skills between expert laparoscopic surgeons and novices could therefore be evaluated using our surgical skill scoring system.