Police detained a local man born in the 1980s, who has initially confessed, Xinhua quoted police as saying. There were no fatalities.
Built in 1786, the Ylivieska church represented tall Finnish wood church architecture. It could seat 700 people. Nothing could be salvaged, vicar Timo Maatta said.
The church had wall paintings by Swedish artist Thomas Kiempe from the 1780s and Sigurd Wettenhovi-Aspa from 1892.
Saturday's fire in Ylivieska culminated in the crash of the tall steeple. Locals spread photos of the scene on social media.
The fire occurred some hours before a scheduled Easter night vigil. After the church was destroyed, around 500 people attended an outside ceremony near the ruins, which was presided over by Oulu Lutheran bishop Samuli Salmi.
Finnish Minister of Education and Culture Sanni Grahn-Laasonen issued a statement deploring the loss of "centuries of local culture".
Church arson is relatively frequent in Finland. In 2006, a young man caused a fire that destroyed the Cathedral of Porvoo, the site of the declaration of Finnish autonomy by Czar Alexander of Russia.