This paper investigates the manner in which decisionmaking is influenced by the impressions given by lifelike agents in negotiation situations. These impressions comprise an agent's facial expressions such as happy and sad, and the history of relationship with the agent. In this paper, we introduce a negotiation game as one of the basic interactions based on the soft game theory. The experimental results reveal that expressions and history significantly influence the receiver's impressions and decision-making. The findings of this study can be beneficial for designing the nonverbal expressions of an animated agent who can negotiate and make a deal with users. Keywords Life-like character, animated agent, game theory, facial expression, appearance, negotiation ACM Classification Keywords