Downey confirmed his salary in an interview with The Hollywood Reporter in which he said he also received back-end compensation for his role in the film.
"Isn't that crazy?" he said. "They're so pissed. I can't believe it. I'm what's known as a 'strategic cost.'"
"The Avengers" is the third-highest grossing film of all time worldwide, the entertainment industry publication said. The film earned an estimated $1.5 billion at the global box office.
Downey's latest film, "Iron Man 3," is expected to gross a $150 million this weekend in its U.S. debut.
The film has already grossed $345.4 million internationally through Thursday, The Hollywood Reporter said.