The majority of the dead were teenagers who were trampled to death, a local doctor said.
Dozens more people were injured and with many being treated for breathing difficulties.
'Hundreds trying to enter'
A 19-year-old witness told Pikiran Rakyat, a local daily newspaper: "Outside, there were hundreds of people pushing to enter. They were pushing at the gate.
"Inside, there were also a lot of people who wanted to leave, because the hall was so packed that it was difficult to breathe."
Another witness said that as the band was playing, hundreds of people forced their way in, damaging the entrance lobby.
An investigation has begun with the 15 concert organisers and others being questioned.
"We received information that before the crush that ended with deaths, concert organisers distributed free drinks.
"There was a smell of alcohol," Suparsono said.
The online news portal Detikcoom reported that about 400 people were in attendance in a building with a 700 people capacity.
Stampedes at concerts and sports events have occurred on a number of occasions in Indonesia in recent years.
A stampede at a football match in the Central Java province in 2006 ended with 10 deaths. The stadium was said to be filled with twice its capacity.
In 2004, two separate concerts by the pop group Sheila had stampedes which ended with eight deaths.