Kevin Cox, 37, was arrested in Delaware and is in custody of state police.
He is likely to be charged with numerous robbery-related crimes. Authorities in Pennsylvania will await his extradition to face charges there.
Cox, of Wilmington, is accused in a number of robberies in both Delaware and Delaware County, Pa.
During the robberies, police say Cox would flash a needle, but did not use it on anyone.
Police say Cox told his victims he is infected with HIV, and the needle is also tainted with the disease.
No injuries were reported during the robbery spree.
