A convoy of the Frontier Corps was moving through Saryab Road in Quetta, the capital of Balochistan province, when the bomb went off, officials told the media.
Three paramilitary personnel were killed instantly and a vehicle was damaged by the blast.
Several passersby were among the injured, who were taken to a nearby hospital. Officials described the condition of two of the injured as serious.
Officials said the bomb was planted in a cycle parked by the roadside.
No group claimed responsibility for the attack.
