Justice H C Mishra allowed the bail after the central investigating agency concluded its arguments.
Sita Soren, sister-in-law of Chief Minister Hemant Soren, has been in jail from February 25 after surrendering before a lower court and her counsel concluded arguments yesterday.
The CBI is investigating the case in which several MLAs from different parties were accused of taking bribe to cast votes in favour of independent candidates.
The 2012 biennial polls were held afresh after the notification was rescinded by Election Commission following seizure of Rs 2.15 crore from a car.