A device hidden in a plastic bag exploded in the hall Tuesday night when people were watching a film at Mingora city, some 150 northeast of Peshawar, the capital of northwestern frontier province, District Police Officer Syed Akhtar Ali Shah said.
He said two men succumbed to injuries at the hospital. A suspect, who was also injured, has been taken into custody.
Shah said the 29 injured, some of them in serious condition, were shifted to a local government hospital.
The bomb was placed under a seat in the last row, the police officer said. An investigation is underway. No one has claimed responsibility for the blast.
Mingora is located in Swat valley, one of the major tourist spots in Pakistan.