Communication surveillance conducted surreptitiously results in wide and severe invasion to people’s privacy so the minimization requirement is a materially important procedural rule in the communication law. J.Y. Interpretation No. 631 clearly indicated that the minimization requirement constitutionally governs the execution of communication surveillance. When determining whether communication surveillance complies with the minimization requirement, courts should consider the totalities of the circumstance to decide whether the law enforcement makes good-faith efforts to minimize the intrusion to nonpertinent communications. In order to ensure the police’s compliance with the minimization requirement, communications obtained by wiretapping violating that requirement should be excluded. Law enforcement officers may adopt spot-monitoring which is able to efficiently lower intrusion to targets and innocent third parties.