To provide a power generating system capable of generating power by using warming-up steam which generates at the time of a restart after a relatively short stop for regular inspections etc, without extensively modifying the existing power generating system.

A discharge pipe 70 connected to a steam pipe 60 is installed; a bypass pipe 80 connected to a condensate tank 40 is installed on the discharge pipe 70; valves 61, 71 and 81 mounted on these pipes are controlled according to temperatures and pressures in the steam pipe 60; and when pressure in the steam pipe rises to the predetermined pressure, the steam in the steam pipe 60 flows to the condensate tank through the discharge pipe 70 and the bypass pipe 80. At this time a power generating means 90 installed on the bypass pipe 80 generates power.