Provided is a chest expander including: a head having a spring installation part at which a spring is installed and arm connection parts installed at both sides of the spring installation part; a pair of arms pivotally coupled with the arm connection parts of the head at their upper ends; a spring member vertically installed at the spring installation part of the head, and converting movement of the pair of arms approached toward each other into a resilient force generated by compressing or extending the spring to vertically transmit the resilient force to the arms; a pair of links having first ends connected to each arm and second ends extending between the arms; and a spring operation part having a link connection part connected to the second ends of the links and compressing or extending the spring member using power added and transmitted to the link connection part through the links by the movement of the arms.