The 40-year-old economist returned from exile in November after reaching an agreement with the junta guaranteeing him free exercise of political activities.
The president of The Transformers party was a virulent opponent of the Deby dynasty that has been in power in Chad for moe than 30 years.
But he was appointed prime minister on January 1.
After unveiling his government programme, Masra won 95.4 per cent of the votes from the 173 deputies of the National Transitional Council, state television said.
He renewed a pledge by transitional president Mahamat Idriss Deby Itno to hold delayed presidential and legislative elections by October 20.
Masra's programme includes an independent justice system, an extra 19 percent in the schools budget and equal access to health care in a system to be built in two years.
Mahamat Deby, an army general, was proclaimed head of an army-run administration two years ago after rebels killed his father Idriss Deby Itno who had seized power in a coup and ruled the desert nation with an iron fist for three decades.
His son promised to hold elections within 18 months before adding another two years of transition before restoring civilian rule.
Mahamat Deby has been designated by his father's Patriotic Salvation Movement (MPS) to stand for president in the forthcoming ballot.
Chad MPs Confirm Former Opposition Leader as Prime Minister
N'DJAMENA - Chad's former opposition leader Succes Masra won a resounding vote of confidence as prime minister on Friday from MPs appointed by the military government.
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