This study is to analyse Satan’s identity in Paradise Lost by examining his dialogues, focusing on his wickedness and his hidden conscience. Chapter II deals with Satan who is called Lucifer as a head of angels but starts a war to compete with God because of his jealousy about God’s omnipotence and dignity. Satan suffers a defeat and falls into a hell without submission to God but he acknowledges his own arrogance and fault in the back of his mind. Chapter III treats Satan who tempts the first human to violate God’s command and eat the fruit of the Tree of Knowledge, by which human comes to be expelled from paradise and get the punishment of ‘death’. But Satan’s conscience feels troubled for a little while at the moment he arrives at Eden. Chapter IV takes Satan for the symbol of wickedness because he enjoys doing evils and even tries to derive vice from virtue as a pastime. Satan even orders ‘sin’ and ‘death’ to kill human but predicts man comes to hit Satan’s head someday. Satan as a main culprit has wicked pride, foolish bellicosity, bad obstinacy and the ability to deceive but his hidden conscience which regrets his own faults and recognizes his wrong pride gives a kind of hope that he may return to Lucifer through repentance and submission to God in the future.