Opposition BJP knowing fully well that numbers favoured Kumar staged a walk out even before the motion was put to vote.
Earlier, a buoyant Kumar slammed BJP saying the united secular forces in the state had "unmasked" its game plan of creating a situation for imposing President's Rule by propping up Jitan Ram Manjhi against him.
"Today they stand unmasked after their gameplan has been foiled by a strong unity among secular forces of JD(U), RJD, Congress and CPI," Kumar said while answering nearly four-hour debate on his confidence motion.
While a total of 140 members voted in favour of the confidence motion moved by Chief Minister Nitish Kumar, there was no vote against it, Speaker Uday Narayan Choudhary announced in the Assembly.
The confidence vote was first approved by voice vote and then on insistence of the government, which had the backing of RJD, Congress, CPI and an Independent, division was taken up.
Altogether 109 JD(U) MLAs except for Jitan Ram Manjhi, 24 of RJD, 5 of Congress, one of CPI and an Independent totalling 140 voted in favour of the government.
All rebel JD(U) MLAs except for Manjhi fell in line to avoid being disqualified by violating whip and voted for Nitish Kumar ministry.
BJP, which has 87 members, walked out of the House beforehand and did not take part either in voice vote or division.
Bihar Assembly has an effective strength of 233 at present with 10 vacancies.
Manjhi skipped the House after raising question how whip is applicable on an unattached member.
Kumar was sworn-in as Chief Minister of Bihar for the fourth time on February 22 last.
Continuing with his tirade against his erstwhile partner BJP, Kumar said Delhi election had heralded the "downhill electoral journey" of BJP which would gain momentum from Bihar where poll was due later this year.
Kumar attacked BJP for propping up outgoing Chief Minister Jitan Ram Manjhi against him and tore into saffron party claim on welfare of mahadalits.
"If you are sincerely in favour of mahadalit than why don't you change your slogan from' Jai Sri Ram' to 'Jai Jitan Ram'," he said mockingly.

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