The 69-year-old Saha was named as the leader of the BJP legislature party hours after the resignation of Deb
Saha joined BJP in 2016 after quitting Congress. He was made party chief in 2020 and elected to Rajya Sabha in March this year.
Deb had taken oath as the first CM of Tripura in 2018, ending the 25-year-rule of the Communist Party of India in the state.
After submitting his resignation to Governor Satyadeo Narain Arya, Deb said he had wholeheartedly served the people of the state.