The 29-year-old man entered the home of Kurt Westergaard on New Year's Day, 2010.
The cartoonist locked himself inside a panic room and was unharmed.
Aarhus City Court ruled on Thursday that the attack was an act of terror. Sentencing is expected to be handed down on Friday.
Mr Westergaard's drawing was one of 12 cartoons of Muhammad published by a Danish newspaper in September 2005, triggering violent protests across the Muslim world.
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