One of the most necessay and basic factor is the people's walking speed on the case when we want to design a lay-out of institutions on a pleasure ground. As many people who visit there are groups of families or friends, their members are interfeted each other of their group walking speed. We have tried to measure that speed as one of probabilitic variables under considerations about the constitution of groups, and factors which may influence upon the speed. Our objects of the measurement are groups of visiters at Yazuyuen and at Toshimaen.3 factors which are road conditions (notation A, 8 levels), group conditions(B, 4 levels). and time table(C, 2levels), have been designed in the orthogonal array table L_32 (2^<31>). And then this designed table has been multiplied by the factor of season(D, 2 levels)and pleasure ground(E, 2 levels). Results of measured group walking speeds are as follows : At Yazuyuen, the total mean value of them is 1.039(m/s)and the standard variation value is 0.193(m/s), and at Toshimaen, the former is 1.051 and the latter is 0.211. The statistical distribution of values of group walking speeds is able to consider as the normal distribution in general, but this type gets out of shape at an space of near shops.