The Boca defender opted not to extend his stay with the Argentine champions, and will now move to the Artemio Franchi after penning a three-year deal with the Viola
Ole reports that the 25-year-old, who has been deployed at right-back under boss Julio Cesar Falcioni since returning from a loan spell at Estudiantes, signed a three-year contract worth around €500,000 a year with the Viola on Monday.
Roncaglia's contract expires at the end of the season and previously refused to extend his stay at his boyhood club after rejecting the offer put his way, meaning he will leave the Bombonera at the end of the 2012 Clausura, currently lead by Boca.
The club are also in the Copa Libertadores semi-finals, and on Sunday beat Deportivo Merlo on penalties to reach the Copa Argentina final and keep their dream of an unprecedented treble alive.
'El Torito' debuted for Boca in 2007, and has since lifted two national championships with the club as well as another Apertura title with Estudiantes.