Evaluation of ship handling mental workload/training has usually depended on professionals (captain, pilot) who have a lot of experience on board. We are attempting to evaluate a ship navigator's mental workload (stress) based on a physiological index. The physiological indices, heart rate variability (R-R interval) and nasal temperature, are good indices of the stress found in ship handling. It is best if we get response and evaluation results quickly on the spot. A recent study shows salivary amylase activity is induced by the sympathetic nervous system; however, a research on ship navigator has not yet accepted worldwide. This article proposes that salivary amylase activity shows a ship navigator's stress during ship handling. Copyright © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.