It is most important to propose the evaluation technique of the unpleasantness which a human body receives due to bridge vibration. In this study, the experiment to measure physiological information was performed in order to propose evaluation technique of serviceability of pedestrian bridges. In the experiment, the vibration of both pedestrian bridges and pedestrians were measured simultaneously, and the relation of both vibration characteristic and the biological pulse wave have been investigated. As the result, it is found that the Lyapunov exponent of biological pulse wave could be used as an index for evaluating the unpleasant bridge vibration which pedestrians feel.
