In total, the Riksdag Administration paid him 250,000 kronor ($37,500) between December 2006 and February 2010, reported news site Nyheter24.
Erik A Eriksson stated that he was careful to check if the sum of the reimbursement was affected if family members shared the apartment.
"I asked the Riksdag Administration on two separate occasions, and was told that there were no restrictions in the matter," he said to news agency TT.
In 2010 he sold the apartment and moved into a home provided by the Riksdag. Even so, he continued to receive rental payments from the Riksdag Administration, which he did not discover until this spring.
On two separate occasions, he called the Administration to correct the faulty payments. But he received a total of 56,000 kronor paid out incorrectly, which he is now paying back in installments.
Anders W Jonsson, the Centre Party's group leader in the Riksdag, told TT that the party has "a great deal of confidence" in Erik A Eriksson.
Erik A Eriksson previously caught the media's attention a few years ago, when he and two Riksdag colleagues allowed oil giant Shell to pay for their trip to France.