A division bench of Justice T.P. Sharma and Justice R.L. Jhanwar pronounced the judgment in a jam-packed court room here, some 110 km from state capital Raipur.
"The high court has largely agreed my arguments in its 20-page judgment that Sen has strong links to Maoists. I am happy that court dismissed the bail application," prosecution counsel and state additional advocate general Kishore Bhaduri, who appeared on behalf of Chhattisgarh government, told reporters after the verdict.
The court had Wednesday reserved its orders after Bhaduri wrapped up his arguments, saying "the seized documents and other evidence were sufficient for not suspending the sentence awarded to Sen by the trial court".
Two women representatives of the European Union had attended the hearing on all three days - Jan 24 and 25 and Feb 9.
Eminent lawyer Ram Jethmalani had opened the arguments for Sen Jan 24, terming the Dec 24 trial court verdict "a case of no evidence" and "political prosecution" in his over two hour-long submission.
Another lawyer, Surendra Singh, who argued in favour of Sen Jan 25, told the bench that "documents were planted by Chhattisgarh Police to establish some connection of Sen with the Maoists".
The trial court verdict on Sen, 61, was widely slammed by human rights activists in India and abroad, who say he was victimised by Chhattisgarh’s Bharatiya Janata Party government for highlighting widespread rights abuses.
Sen is at present lodged in the Raipur central jail. The trial court also awarded life terms to Maoist ideologue Narayan Sanyal and Kolkata-based businessman Piyush Guha. Sen was accused of acting as a courier between Sanyal and Guha.