Ewing said: "Undergrounding on such a large scale would cost an estimated £263 million and require large sealing end compounds at the points where the line is undergrounded, which would have a significant landscape impact in their own right.
"According to the report of the public inquiry and external consultants, the impacts of the consented line at Stirling are moderate so I have concluded that due to the costs, technical problems and limited environmental benefits, the case for undergrounding has not been justified."
The decision was attacked by Scottish Conservative MSP for Mid-Scotland and Fife, Murdo Fraser, who said: "The announcement by the minister today of the approval of the Scottish Power visual impact scheme is a slap in the face of the people of Stirling.
"The additional mitigation measures amount to very little given the huge visual impact of the new pylons close to the Ochils and the Wallace Monument."
He said that the costs of undergrounding were "minimal" compared to the money the government is spending on renewable energy projects.