2. Inspection of import and export mail: Customs clearance of mail, other than personal correspondence
under Articles 256 and 257 of the Customs Act;
3. Communications with persons under detention or in prison: Control of communications with the
persons under detention or in prison under Article 91 of the Criminal Procedure Act; Article 131 of the
Military Court Act; Articles 41, 43, and 44 of the Administration and Treatment of Correctional
Institution Inmates Act; and Articles 42, 44, and 45 of the Act on the Execution of Criminal Penalties in
the Armed Forces and the Treatment of the Military Inmates;
4. Communications with persons declared bankrupt: Where a trustee in bankruptcy receives
communications addressed to a person declared bankrupt under Article 484 of the Debtor Rehabilitation
and Bankruptcy Act;
5. Monitoring radio waves for the elimination of interference, etc.: Where radio waves are monitored in
order to maintain order in radio waves by, for example, eliminating interference under Articles 49
through 51 of the Radio Waves Act.
(2) Any censorship of mail or any wiretapping of telecommunications (hereinafter referred to as
"communication-restricting measures") shall be used as a supplementary means of facilitating a criminal
investigation or ensuring national security, and efforts shall be made to minimize the violation of people's
communication secrets. <Newly Inserted on Dec. 29, 2001>
(3) No person shall provide or be provided with an electronic serial number: Provided, That this shall not
apply where an enterprise for manufacturing mobile phones or a mobile communications business entity
provides or is provided with an electronic serial number for a performance of lawful business, such as the
opening of a service for mobile phones and repairs. <Newly Inserted on Jan. 29, 2004>
Article 4 (Prohibition of Use of Contents of Mail Obtained through Illegal Inspection and Contents of
Telecommunications Obtained through Illegal Wiretapping as Evidence)
Mail or its contents obtained through illegal inspection and the contents of communication acquired or
recorded through illegal wiretapping in violation of Article 3 shall not be admitted as evidence in a trial or
disciplinary procedure.
Article 5 (Requirements for Permission for Communication-Restricting Measures for Criminal
Investigations)
(1) The communication-restricting measures shall be allowed only when there is a substantial reason to
suspect that the following crimes are being planned or committed or have been committed, and it is
impracticable to otherwise prevent a crime, arrest the criminal, or collect the evidence: <Amended on Dec.
13, 1997; Jan. 12, 2000; Dec. 29, 2001; Dec. 21, 2007; Apr. 5, 2013; Jan. 6, 2015; Jan. 6, 2016; Jan. 6, 2016; Dec.
31, 2019>
1. Part II of the Criminal Act - Chapter I Crime concerning Insurrection, crimes under Articles 92
through 101 from Chapter II Crimes concerning Foreign Aggression, crimes under Articles 107, 108,