This paper investigates on whether there is the asymmetric relation between initial margin requirements and volatility across bull and bear markets for Japanese TOPIX and NIKKEI225 index during 1970-1999. We use regression in levels to scrutinize relation between margin requirements and volatility. We find that there is negative relation. This result is confirmed significantly by bootstrap simulation. The findings show that margin requirement affects and causes stock return volatility. Thus higher margin requirements are associated with lower subsequent stock market volatility across during normal, but show no relationship during bull and bear markets from regression and EGARCH model. As matter of fact, we conclude no evidence that there is an asymmetric process, i.e., pyramiding and depyramiding effect in terms of bull and bear markets from Japanese TOPIX and NIKKEI225. However, for normal periods, we find that there is evidence of asymmetric process in Japanese stock market. In conclusion, we confirm that the policy tool of margin requirements does not work when stock market is in crash or bubble state.