This study on diving accidents intends to clarify and deepen our under-standing on the causes and mechanism, and to examine on the possibility of safety measures.
　For these purposes,the following procedures are taken;
　　1. studying the physical structure of pool and the actual situation of instruction, from the 22 legal cases and 26 judicial decisions on diving accidents,
　　2. inquiry into 198 swimmers on their own experience of accidents and
　　3. video - recording the motion of diving,comparing the motions of diving into a 1.5m deep pool and a 0.8m deep pool
　As the result,the following points became clear;
　　1. The swimming pool should be sufficiently structured to prevent any accidents caused by diving under normal conditions.
　　2. The instructors are not fully aware of the possible dangers that may be caused from diving.
　　3. 16.16% of the swimmers had reported that they have the experences of actually colliding their head with the bottom floor of pool, and this indicates the possibility of leading into a serious accident from a minor cause.
　　4. The motion of the diver before entering the water is adjusting the motion underwater, and it further became clear that the position and the direction of the upper body and the beating of water by the lower body are significant factors in determining the ability of adjusting directions underwater.
　In conclusion, the diving accidents in swimming pools occur from compound factors acting simultaneously, namely, ( 1 ) the swimmer himself, ( 2 ) the form of diving, ( 3 ) the physical structure of pool and ( 4 ) instruction and management.
　It is important to understand the causes and mechanism of diving accidents, and to be aware of its danger. Furthermore the effective method for establishing safety measures through instruction and management shall be endeavoured.

DESCENTE SPORTS SCIENCE Vol.18/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE