The bomb went off hidden beside a car parked near Science College on Jinnah Road, officials said, the Indian Express reported.
Jinnah Road is one of Quetta’s main thoroughfares and busiest shopping districts. Officials are assessing the type of bomb.
The deceased and injured have been shifted to Quetta Civil Hospital. Officials said nearby buildings had broken glasses after the explosion and most of the injured suffered from shrapnel and nail injuries.
The explosion site is barely 2 km from the four-star Serena Hotel in the city, where a powerful bomb took the lives of five people and injured dozens of others in April this year.
The Chinese Ambassador was lodged at the hotel at the time but he was away on an official dinner.
The restive Khyber Pakhtunkhwa and Balochistan provinces have become the hotbed of terror attacks in recent years.