Federal Election Commission reports filed over the weekend show incumbent Republican Joe Wilson and Democratic challenger Rob Miller had combined to spend $5.8 million as of the end of September.
The reports show the candidates had $1.5 million more combined on hand for the last month of the campaign.
Wilson is running against Miller in a rematch of their race of two years ago in which they spent only $1.8 million combined.
Wilson gained notoriety outside the state for shouting "You lie!" at President Obama during a health care speech to Congress in September 2009. Money poured into both campaigns after Wilson heckled the president.
For the last weeks of the campaign, Wilson has more than $1 million on hand. Miller had $519,000 to campaign in the district reaching from the Midlands south to the coast.
The average spending by a House candidate has been $650,000 this election season, according to opensecrets.org, which tracks campaign financing around the country.
The group said the most expensive congressional race in South Carolina until this year was in 2006. That year, incumbent Democrat John Spratt defeated Republican Ralph Norman in the 5th District on the northern edge of the state in a race where the two candidates together spent $3.6 million.