Especially targeted at children and minors, sex crimes including murder, violent crime continued to receive media attention, and each time to demand preventive measures. Public opinion became the seething. In response to these media and public, before and after 2010 by introducing the new science technology to prevent sex offender, Registration and Releasing Identies System, Recidivism Control System, Electronic Monitoring System was introduced. These institutions was aiming to appropriate role to prevent sex crimes and now became time to seek the power, and assessing what works. Evaluating based on statistics of the new systems in sex crimes, Electronic monitoring system is ‘very effective’ and Recidivism Control system is ‘pros and cons in progress', Registration and Releasing Identies system is can be summarized as ‘question effectiveness’. Based on this assessment, Electronic monitoring system need to broaden the scope and Registration and Releasing Identies system need to reducing the target and Recidivism Control system is expected to future enlargement should reexamine whether or not.