To provide an excavation working device preventing an intrusion of excavated materials to a device principal section.

In the excavation working device in which a casing 100 passed in a revolution body 15 is held by inserting a plurality of chucks 21 between the casing and the revolution body 15 and the revolution body 15 is rotated with high torque by driving motors 11 connected to the revolution body 15 through speed reducers while the casing 100 is turned and pressed into a ground by lowering lifting-lowering frames 5 on which the revolution body 15 is mounted, the excavation working device has the first covers 31 installed so as to be projected extending over the upper section of the revolution body 15 from each chuck 21 and the second covers 32 suspended to the inner circumferential surface of the revolution body 15 from upper sections among each chuck 21.