An embodiment of the present invention provides an apparatus and method for expanding skin capable of expanding autologous skin to the maximum extent and performing a tissue culture of skin at the outside of the body. While an apparatus for expanding autologous skin of body's outside in general takes a form of expanding skin by applying a certain amount of constant force for a period of time regardless of the skin properties, the apparatus and method for expanding skin according to the embodiment of the present invention expands the skin to the maximum extent without rupturing the skin based on measurements of elasticity of the skin to find the maximum expanded area reachable just before rupturing of the skin.