This article summarizes the differences between self-reported and non-self-reported methods for measuring emotions. It also provides an overview of previous studies that examine the indexes related to these methods, mainly in the field of affective trait research. Finally, the article discusses the application of explicit and implicit measures. The main arguments of this article are as follows: (1) There is no superiority or inferiority between explicit and implicit measures, such that one is superior to the other or one could be used as a substitute for the other. (2) Explicit and implicit measures have advantages and disadvantages and should be used with an understanding of their respective characteristics.