The prefecture was hit by a deadly earthquake in October. The Meteorological Agency said the earthquake, whose focus was around 10 km (6 miles) deep, shook the region at around 6:30 p.m. (0930 GMT).
There were no immediate reports of injuries of damage, public broadcaster NHK said.
NHK added that some of the high-speed bullet trains in the area were halted for inspections.
The same region was hit by a 6.8 magnitude tremor in October, which killed 40 people, the deadliest tremor since a 7.2 quake killed more than 6,400 in the city of Kobe in 1995.