The donation by the Oscar-winning actor will help provide shelters and medical and psychological rehabilitation services, said Larry Cox, executive director of Amnesty International USA.
Cox accepted the donation Wednesday at a United Nations Conference in New York. Amnesty International will administer the funds.
"I understand that this pledge is not a solution for the problem," Cage, 42, said when he announced the contribution by video.
"It's my hopeful wish that today's discussions on this tragic subject at the United Nations conference may bring us closer to eradicating the nightmare of child soldiers."
Cage said he has worked with Amnesty International for more than two years.
The United Nations estimates there are at least 300,000 child soldiers participating in armed conflicts in the world today.
Cage won an Oscar for his role in 1995's "Leaving Las Vegas." His screen credits also include "Adaptation" and the upcoming "World Trade Center."