The charity says the number of deaths has accelerated in the last six months.
Just under 100 children are thought to have died from contracting Ebola in the six months following 1 August 2018, when the outbreak began.
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In the next six months, more than four times as many children have died.
“This is another grim milestone in a crisis that is devastating children in its path, especially the youngest,” said Heather Kerr, Save the Children’s country director in the DRC.
“The virus has been speeding up over the last six months instead of slowing down, and we’re seeing a bad scenario unfolding right in front of us, as there are now four cases in Goma, a city of more than one million people.”
Over the last year and a half, 737 children are thought to have contracted the disease.
As the DRC struggles to contain Ebola’s spread, officials have joined forces with Rwanda to discourage travel across the border between the nations.
People travelling across the border for non-essential reasons will need clearance from both governments, according to Rwandan and Congolese health officials who met on Tuesday.
Rwanda briefly closed its border with the DRC last week after a patient tested positive for Ebola in Goma, a Congolese city of more than a million people which is near Rwanda’s main border town of Gisenyi.
In a separate measure to control the spread of the disease, churches in Rwanda have advised people not to shake hands.
“The WHO declared this an emergency of international concern, and that should really mean the international community steps up its support,” Ms Kerr said.
“Contacts of the sick need to be traced, patients need to be looked after, the dead need to be buried safely and above all, trust needs to be built with the communities so that the message that Ebola is very real, and that it kills, is understood.”
There is no licensed treatment for Ebola, which is spread by close contact with bodily fluids, and survival can depend on seeking treatment as quickly as possible.
But many people in the region do not believe the virus is real and choose to stay at home when they become sick, infecting those who care for them, say health workers.
This outbreak is second in size only to the 2014-16 outbreak in west Africa that killed more than 11,300 people.
Additional reporting by agencies