Governor Zulfiqar Ali Magsi was travelling from Kalat to provincial capital Quetta when a bomb planted by the highway went off in Mangochar area, police said.
One of the cars in the motorcade suffered slight damage though no one was injured by the blast. Officials said a low intensity bomb was used in the attack.
Security forces cordoned off the area and launched a search for the attackers.
The Governor had gone to Kalat to condole the death of a legislators mother. No group claimed responsibility for the bombing.
Authorities usually blame such attacks in Balochistan on nationalist groups waging a campaign for greater autonomy.