In this paper I clarify some characteristics of David Hume's "self-love" and thereby consider the role of "reflection" in his theory of passion. To begin with, I look into the usage of self-love in Hume's work, and show its various aspects. Then I examine some related notions such as selfishness and self-interest, and point out their similarities to self-love. Moreover, I analyze it more closely, comparing with Joseph Butler's "self-love." My conclusion is that Hume's self-love is essentially a calm passion assisted by reflection or reason. Next, on the basis of this conclusion, I discuss Hume's view on the functions of reflection, and indicate that, in addition to his official view, there must be two more functions in his idea of reflection. One is to balance interests or to weigh advantages, and the other is to form rules of conduct and measures of preferences. Finally, I make a brief examination of four significant problems with relation to Hume's self-love and reflection: (1) the status of Hume's "general appetite to good," (2) the relation between a general idea and a particular one, (3) the influence of custom on passions and reflection, and (4) Hume's view of human being.