If you like ice cream, Miyahara (宮原眼科) is definitely a must. With lots of interesting and unique flavors, Miyahara is a favorite among tourists and locals a like.
The inside of the Miyahara looks like an old library or book shop. If you don't like ice cream, you can buy chocolate or pineapple cake instead.
Only a quick walk down the street from the Taichung Train Station (台中火車站), Miyahara will be easy to spot--just look for a long line.