In order to understand quantum gravity on cosmological backgrounds, dS/CFT correspondence is expected to play important roles. However, it has not been well understood yet compared with AdS/CFT correspondence. One of the reasons is that currently very few concrete examples are available and only generic arguments can be made. Recently, we provided a concrete proposal of dS_3/CFT_2 correspondence by making use of Chern-Simons description of (higher spin) gravity. In this talk, we will explain our proposal and supporting arguments by examining partition functions, correlation functions and so on.