At least one person has died after contracting the virus in the country's north-east, the WHO says.
The Congolese health ministry had notified the WHO of a "lab-confirmed case" of Ebola, it added on Twitter.
More than 11,000 people died in the Ebola outbreak in West Africa in 2014-2015, mainly in Guinea, Sierra Leone and Liberia.
The last outbreak of Ebola in the Democratic Republic of Congo was in 2014 and killed more than 40 people.
