"At least six people have been killed and more than 15 injured. The bomb was planted on a motorcycle," police official Qamar Ul Hasan said.
Hasan said the target of the attack was yet not clear.
"The bomb also badly damaged around five to six shops and destroyed some motorbikes and other vehicles," he said.
There was no immediate claim of responsibility.
Baluchistan, which borders Afghanistan and Iran, is plagued by Islamist militancy, attacks on the Shiite Muslim minority and a separatist Baluch insurgency.
The violence has raised concerns about security for Pakistan's general election, due to be held on May 11 and marking the country's first transition of power between two elected civilian governments.
Zulfiqar Ali, a second police official, confirmed the attack and warned that the death toll could rise further.
"All those killed were civilians," Ali informed.