Red queen crab Chionoecetes japonicus have been caught mostly with long line pots in the Sea of Japan. The capture of female and sublegal-sized male (≤90 mm carapace width) is prohibited and these crabs must be returned to the sea by fishery regulations. In actual operations, however, females are as likely or more likely to be caught as males. To reduce the bycatch of females and sublegal-sized males, the effects of soak time and the capture characteristics by sex were investigated. The experimental operations used with commercial pots were carried out off west of the Oki islands in the Sea of Japan in 1992 and 1993. The capture of females and small-sized males (<95 mm carapace width) was reduced by increasing the soak time. A large number of females were caught convergently by a small number of pots because the distribution of females was more contagious than that of males. To reduce the bycatch, therefore, the soak time can be determined to be the most important factor.