The Defense Ministry destroyed around 34,300 secret documents during the five years through 2011, ministry spokesman Masayoshi Tatsumi said.
The ministry is expected to face criticism from opposition parties before the start of Diet discussions on a state secrets protection bill aimed at strengthening penalties on government officials who leak secrets on foreign and defense policies.
Defense secrets are decided on by the defense minister under the revised Self-Defense Forces law that took effect in 2002. The minister designates defense secrets from information gathered by the SDF as well as information about SDF operations.
Such secret documents should be kept for up to 30 years. Although documents can be kept beyond 30 years, they can be destroyed with the approval of a senior ministry official.
If the state secrets protection bill is enacted and comes into force, defense secrets will be managed as designated state secrets.
Tatsumi said at a news conference Tuesday that the defense minister has instructed officials to not destroy defense secrets.