Provided is a method for producing low-molecular-weight polytetrafluoroethylene which is less likely to generate C6-C14 perfluorocarboxylic acids and salts thereof. The disclosure relates to a method for producing low-molecular-weight polytetrafluoroethylene having a melt viscosity at 380° C. of 1.0×102 to 7.0×105 Pa·s. The method includes (1) irradiating high-molecular-weight polytetrafluoroethylene with radiation in a substantially oxygen-free state and decomposing the high-molecular-weight polytetrafluoroethylene into a low-molecular-weight component and (2) deactivating, in a substantially oxygen-free state, at least part of main-chain radicals and end radicals generated by the irradiation and providing the low-molecular-weight polytetrafluoroethylene.