This first Superman comic book sold for $1 million US on Monday, more than 70 years after it hit the stands for 10 cents. (Comic Connect Corp./Associated Press)

A copy of the first comic book featuring Superman, considered the holy grail of comic collecting, sold for $1 million US on Monday.

The sale, on auction site ComicConnect.com, set a record for a comic sale. The previous record was estimated at just over $400,000 US.

The buyer Monday was a New York-based collector, according to a ComicConnect.com spokesman.

"It's considered by most people as the most important book," said John Dolmayan, a comic book enthusiast and dealer. "It kind of ushered in the age of the superheroes."

This copy got a better price than earlier copies of the same comic at auction because it is in better condition, Dolmayan said.

The 1938 edition of Action Comics No. 1 has Superman lifting a car on its cover. It originally sold for 10 cents.

The action hero genre caught on almost immediately and the Superman comic book series followed in 1939.