This study examines Locke''s view on death penalty and looks for some ideas to solve the issue for and against death penalty and to establish a better criminal policy. According to Locke, people leaving from the state of nature contract with each other and establish a civil society in order to protect life, liberty, and estate. In the civil society, they give up the right of punishment that they had in the state of nature. The state of the civil society comes to have a common law, a judge, and a executive power, and serves to protect life, liberty, and estate. Death penalty is justified on two grounds in the civil society as well as in the state of nature. The two grounds are the forfeiture of the right of life by "some act that deserves death," and the notion of retributive and utilitarian punishment. Death penalty is allowed because the inalienable right of life is forfeited due to violence with an intention of killing or a murder crime on the one hand, and because reparation and restraint in proportion to crimes are required one the other hand.