Construction machine

A construction machine comprising:

• a lower traveling body;
• an upper rotating body mounted on said lower traveling body rotatably about a vertical axis and comprising an upper frame, said upper frame having a base plate and a floor plate disposed spacedly above said base plate;
• a plurality of hydraulic actuators;
• a plurality of control valves for controlling said hydraulic actuators each individually;
• a plurality of operating valves for operating said control valves each individually;
• an operation pattern switching valve for switching combination patterns of said operating valves and said control valves from one to another;
• an operator's seat mounted over said upper frame through a seat frame, said operation pattern switching valve being installed in a stand-up attitude within an underfloor space, said underfloor space being formed between said base plate and said floor plate at a position near the right or left foot of an operator sitting on said operator's seat;
• and
• an operating lever for a switching operation disposed on an upper surface side of said operation pattern switching valve, said operating lever is configured so as to be manually operable from an operation port formed, said operation port being formed so as to be open to said floor plate, said operation pattern switching valve being inclined forwardly downward so that an upper surface side thereof including said operating lever faces said operation port.