The deal is being viewed as the biggest ever single investment in mainland Norway.
“This is one of the biggest plane orders in the world and the biggest in Europe,” spokeswoman Anne-Sissel Skånvik told news agency NTB.
“We can afford it. The deliveries will start in 2016 and we have several possibilities for financing.”
The budget carrier said it had signed agreements for 122 aircraft from Boeing and 100 from Airbus.
The order includes 100 of the new Boeing 737 MAX8 and 22 Next-Generation 737-800, the company said, as well as 100 Airbus A320neo.
“We have secured our fleet renewal for years to come and are very pleased with the agreements with both Airbus and Boeing,” said CEO Bjørn Kjos in a statement.