Biden made the announcement just days before he leaves his office.

Biden's son was convicted early this year on federal gun and tax charges.

He was set to appear soon in Delon, California.

With this decision, Joe Biden made a U-turn on his previous announcement that he would not use the extraordinary powers of the presidency to benefit his family members.

According to reports, US-President elect Donald Trump cannot revoke the official grant of clemency after he takes charge in the upcoming days.

Speaking of his decision, Biden said, "Today, I signed a pardon for my son Hunter. From the day I took office, I said I would not interfere with the Justice Department’s decision-making, and I kept my word even as I have watched my son being selectively, and unfairly, prosecuted."

Biden said Hunter was singled out only because he was his son.

"No reasonable person who looks at the facts of Hunter’s cases can reach any other conclusion than Hunter was singled out only because he is my son – and that is wrong," Joe Biden said.

He said: "In trying to break Hunter, they’ve tried to break me – and there’s no reason to believe it will stop here."

"The charges in his cases came about only after several of my political opponents in Congress instigated them to attack me and oppose my election," Biden said.