The aim of the present study was to examine how the prior experience and social influence affect the escape in the emergency situation. An experiment was conducted with 3×2 factorial design on the prior experience (exploration, fear and no) and test situation (individual or collective). The mice of the CS strain were randomly assigned to one of the six groups. The prior experience was always given in individual condition. In the test, mice were required to escape from water gradually risen. Only the prior experience with environment facilitated the time for entrance to the safety zone (escaping time) in both individual and collective conditions. On the other hand, interaction effect was obtained for the time of climbing the slope (climbing time): Inthe collective situation, the fear experienced group climbed the slope faster than the other two groups, while in individual condition, group exploration experienced group showed faster running than the others. A possible explanation for these results was discussed in connection with implication of the measures and the structure of apparatus.