The quake struck at 12:18 pm (0418 GMT), with the epicenter located 54 kilometers (33 miles) off the island's east coast, at a depth of around three kilometers, it said.
Taiwan, which lies near the junction of two tectonic plates, is regularly hit by earthquakes.
The worst recorded, measuring 7.6 on the Richter scale, hit the island in September 1999 and left some 2,400 people dead.