The 45-year-old man, whose identity has been kept under wraps, was held in the town of Siedlce after his daughter, now aged 21, reported the alleged abuse. According to the police officials, she gave birth to two children in 2005 and 2007, adding that "they were probably a result of rape". The cops said that the Polish dad watched over both births in hospital - then forced her to leave the kids, now aged three and 20 months, and return to her dungeon.
The woman escaped the home in the village of Grodzisk, east Poland, last week and went to police with her mum - who is being quizzed over how she did not know what was going on.
The dad tried to flee to Italy - but was caught at a train station.
He denies rape charges but refuses to talk to cops.
A judge ordered the detention of the suspect for three months pending the completion of the investigation.
"The picture the girl painted was really horrific," The Sun quoted a police spokesman, as saying.
The case mirrors the plight of Elisabeth Fritzl, 42, who was held as a captive in a soundproof underground dungeon for 24 years in Amstetten, Austria by her dad Josef.
She gave birth to seven children by dad Josef, 74 - who now faces up to 3,000 rape charges.