Reuters reports that the case was identified in the eastern state of Brandenburg over the weekend.
The new discovery brings total confirmed cases to 35 since the first one on 10 September. All were in wild animals with no farm pigs affected, the ministry said on its website.
All have been found in the Brandenburg area. Germany's Friedrich-Loeffler scientific institute had confirmed the latest animal had ASF, the ministry said.
China and a series of other pork buyers banned imports of German pork this month after the first case was confirmed, causing Chinese pork prices to surge.
The disease is not dangerous to humans but it is fatal to pigs. A massive outbreak in China, the world's biggest pork producer, has led to hundreds of millions of pigs being culled.
The German government is considering aid to farmers after pork prices fell, agriculture minister Julia Kloeckner said on Friday 25 September.