KCNA news agency reports that the North Korean leader cut the ribbon at the opening of a fertiliser factory.
It adds that people at the factory “broke into thunderous cheers of hurrah” when he appeared on Friday.
The reported appearance – his first since an event on state media on 12 April – comes amid global speculation over his health.
The latest reports from North Korean media could not be independently confirmed.
State media later released images that it said showed Mr Kim cutting a ribbon outside a factory.
Asked about Mr Kim’s reported reappearance, US President Donald Trump told reporters that he didn’t want to comment yet.
According to Korean Central News Agency (KCNA), Mr Kim was accompanied by several senior North Korean officials, including his sister Kim Yo Jong.
The North Korean leader cut a ribbon at a ceremony at the plant, in a region north of Pyongyang, and people who were attending the event “burst into thunderous cheers of ‘hurrah!’ for the Supreme Leader who is commanding the all-people general march for accomplishing the great cause of prosperity”, KCNA says.
Mr Kim said he was satisfied with the factory’s production system, and praised it for contributing to the progress of the country’s chemical industry and food production, the state news agency adds.
Speculation about Mr Kim’s health began after he missed the birth anniversary celebrations of his grandfather, state founder Kim Il Sung on 15 April.
The anniversary is one of the biggest events in the North Korean calendar, and Mr Kim usually marks it by visiting the mausoleum where his grandfather lies. Mr Kim had never missed this event.
Claims about Mr Kim’s ill-health then surfaced in a report for a website run by North Korean defectors.
An anonymous source told the Daily NK that they understood he had been struggling with cardiovascular problems since last August “but it worsened after repeated visits to Mount Paektu”. (Courtesy BBC)