Roppongi Hills "Observatory Tokyo City View"
Roppongi Hills features an indoor observation corridor, "Tokyo City View". Tickets can be purchased at the general ticket counter on the third floor, and visitors can then take a dedicated elevator to the 52nd floor.
Out of all the observation decks in Tokyo where you can see the night view, I personally think Roppongi has the most beautiful one. You get a full 360-degree view, and it's open until 1 a.m., so you can really enjoy Tokyo's nightlife.