Establishment heavyweight Cantor lost his seat to an even more conservative but virtually unknown Tea Party-backed challenger in a June election amid deep divisions within the Republican Party ahead of November's congressional vote.
But he had been expected to see out the remainder of his term, which ends in January. Cantor said he now plans to leave Congress on August 18.
"I want to make sure that the constituents in the Seventh District will have a voice in what will be a very consequential lame-duck session," he told the Richmond Times-Dispatch late yesterday.
Holding such a special election for his seat in November would allow the winner to take office immediately, rather than in January with the next congressional session.
"That way he (the winner) will also have seniority, and that will help the interests of my constituents (because) he can be there in that consequential lame-duck session," Cantor explained.
Kevin McCarthy replaced Cantor as House majority leader.