A working machine is provided with: a frame for the working machine; an engine supported within the machine compartment of the working machine by the frame; an exhaust gas purification device having a filter for collecting particulate matter contained in the exhaust gas discharged from the engine; a compartment cover for defining the machine compartment; a compartment cover support member which is a member for supporting the compartment cover and which is provided on the frame; an engine hood supported by at least the compartment cover support member and having a top plate which covers the machine compartment at a position above the engine, an opening which is provided in the top plate in order to allow the upward extraction of the exhaust gas purification device from the machine compartment, and a reinforcement member which is disposed at the peripheral edge of the opening and which carries the load of the exhaust gas purification device; an exhaust gas purification device support member for supporting the exhaust gas purification device in such a manner that the exhaust gas purification device is suspended downward through the opening; and an opening cover removably mounted to the engine hood and closing or opening the opening. The exhaust gas purification device support member has a mounting section which is mounted to the exhaust gas purification device and an affixation section which is supported by and affixed to the reinforcement member. When the affixation of the affixation section is released, the exhaust gas purification device support member can be removed to a position above the opening together with the exhaust gas purification device which is mounted to the mounting section.