Xing Er, a six-year-old male panda — soon to be seven — then took a tour of the zoo, which was closed at the time.
He was spotted on a surveillance video “leaving his enclosure, slipping under an electric fence”, zoo spokesman Jacob Munkholm Hoeck told AFP.
The animal wandered around the zoo until an employee noticed it and called a security team.
“The veterinarian of the zoo anaesthetised the panda and he was brought back to the enclosure,” Hoeck said.
“There he was given an antidote and woke up a couple of minutes later.”
Xing Er was not harmed and there were no human injuries.
Bengt Holst, the zoo's chief scientist, said in a statement that security around the enclosure will be “carefully examined” to “make sure (it) doesn't happen again”.
Xing Er and his female mate Mao Sun — who did not take part in his escape — arrived in Denmark in April 2019, on loan from the Chinese city of Chengdu.
They are a part of the “panda diplomacy” programme set up by China which consists of lending pandas in order to foster relations with trading partners.