Provided is a method of recovering gaseous hydrocarbons and/or liquid hydrocarbons from underground, characterized by using a polylactic acid) resin comprising an a poly-L-lactic acid component and a poly-D-lactic acid component and having a heat of fusion at 190° C. or higher, as measured by differential scanning calorimetry, of 20 J/g or more, wherein the underground is at a depth of 3,000 m or deeper.According to the recovery method of the present invention, shale gas, shale oil, and the like can be recovered efficiently.