"The Bihar government has already announced to waive off tax on the film 'Manjhi-the Mountain Man'," Kumar told reporters on the sidelines of "Janata Ke Darbar me Mukhya Mantri" programme.
The film is based on the life of Dashrath Manjhi, a poor labourer hailing from Gehlaur village in Gaya district widely known as the "Mountain Man".
He had laid a road through the mountain using only hammer and chisel in memory of his wife who passed away without medical treatment as travel to the nearest hospital took a lot of time due to the mountain.
The film is scheduled for release on August 21, 2015.
Kumar is scheduled to attend a programme on the movie in the evening.
The cast of the film paid a visit to Gaya last evening as a part of an event to promote the movie.