Balochistan was rocked by a series of attacks late last year that claimed over 180 lives and raised concerns about a growing terrorist presence, including fighters affiliated with Islamic State, which has claimed several bombings in the province.
The violence has raised concerns about security for projects in the $57 billion China Pakistan Economic Corridor, a planned transport and energy link from western China to Pakistan's southern deep-water port of Gwadar.
"Three individuals have embraced martyrdom including (Additional Inspector General) Hamid Shakeel and his driver," provincial government spokesman Anwar Ul Haq Kakar told Reuters.
Shakil was on his way to work in the provincial capital, Quetta, when the bomb exploded, targeting his vehicle, Balochistan police Inspector General Moazzam Jah told Reuters.
Three police officials were seriously wounded, he added.
(Additional reporting and writing by Saad Sayeed; Editing by Nick Macfie)