Ford spokesman Todd Nissen said the plant in Genk will close beginning April 4.
The company had planned to idle the plant in May for another reason, but it moved up the date after auto parts suppliers in Japan were damaged by the twin disasters on March 11.
"We didn't run short of parts, but if we can find things to do to conserve parts it certainly makes sense to do that," Nissen said.
Ford makes Mondeo sedans and Galaxy and S-Max minivans at the Belgian plant.
Ford has also canceled overtime at three plants in the U.S. and one in Thailand.
Crucial Japanese parts and other supplies aren't reaching factories because of quake damage and power outages in that country. That has interrupted car production around the world.
After a Japanese plant that makes pigment for auto paint was damaged, for example, Ford told dealers to stop taking new orders for F-150 and Super Duty pickups and Expedition and Navigator SUVs in "tuxedo black," a color that uses the pigment.