There is provided an axial flow turbine capable of realizing a reduction in gland leakage amount. The axial flow turbine in an embodiment is of a single flow type and includes an upstream-side gland part located on an upstream side of a working medium in an axial direction of a turbine rotor and a downstream-side gland part located on a downstream side of the working medium in the axial direction of the turbine rotor. The axial flow turbine is configured such that a cooling medium lower in temperature and higher in pressure than the working medium is extracted in a middle of flowing from the inside to the outside of the turbine casing in the upstream-side gland part, and the extracted cooling medium is introduced into the stationary blade.