In order to do morally right behavior that we cognitively know, prosocial moral motivation is necessary. Previous studies revealed emotion is important for prosocial moral motivation. This was supported by cognitive neuroscience studies using functional magnetic resonance imaging(fMRI) in which the activity of ventral striatum(VS) was observed when people made moral decision. VS was originally known as the core area of reward process but recently VS was found to respond also to social reward and even feeling of prosocial emotion itself. However it is not clear why VS was activated when people experience prosocial moral sentiments. The aims of this review article were to find situations in which people are prosocially and morally motivated and to understand more about the role of emotion as a moral motivator by examining evidence regarding the neural network, including VS, of prosocial moral motivation and moral decision-making.