The Moroccan is the latest person to be arrested as part of an anti-terror sweep being carried out by Digos, Italy's anti-terror police squad, Il Sole 24 Ore reported.
Twelve other arrests were made last week.
Ten people were accused of planning to fight in Syria alongside Isis jihadists, while two others were suspected of being part of an al-Qaeda-inspired cell that was planning attacks in Italy and North Africa.
The Isis-related probe began in October after authorities became aware that an Italian female convert to Islam, Maria Giulia Sergio, 28, had joined the ranks of Isis after marrying an Albanian with the same intention.
The couple and the husband's mother travelled to Syria via Turkey several days after their September wedding, police said.
He was immediately dispatched to an Isis training camp while Sergio was given weapons training and sent messages to friends celebrating the deadly January attack on French satirical magazine Charlie Hebdo.
Sergio persuaded her parents and a sister, also Muslim converts, to join her in Syria. The family had sold their furniture and requested passports before their arrests on Wednesday for "organizing a journey for terrorist ends" - a recently introduced offence which was applied for the first time in his case.
Five members of the husband's Albanian family were arrested, including his father, Baki Coku, 40, who was detained in Albania and is now subject to extradition proceedings. The suspects also included a Canadian long-time resident of Italy.
Italy raised its terror alert level following the deadly attacks in France, Tunisia and Kuwait in late June.