A reactor for processing organic waste includes a steam supply pipe installed in a reaction vessel such that steam supplied from an external steam supply device can be supplied into the inside of the reaction vessel. The steam supply pipe has a plurality of steam supply holes so as to supply the steam supplied from the steam supply device to the waste in the reaction vessel through the holes. An organic waste processing apparatus comprising the reactor having the configuration above is provided. Heat due to the steam supplied to the reactor is uniformly supplied to the waste in the reactor within a short time, and thereby increasing processing efficiency.