To provide a rotary table device enabling an upper working space to be used as a wider space by further decreasing the height of a table base of the device, and making work using a small crane possible, in the rotary table for a rotary drilling machine.

A rotary table device A for a rotary drilling machine, which drills a hole in the ground while rotating the rotary drilling machine which is passed through a drive bush 2 by the drive bush 2, comprises: a table base 1; a lifting device 400 holding and raising/lowering the rotary drilling machine; a fall preventing stopper 8 for stopping the rotary drilling machine to prevent it from falling when removing an extended body in an upper part of the rotary drilling machine; and a plurality of expansion legs 11 provided on sides of the table base 1 and having lower ends grounded on a ground surface. Each of the expansion legs 11 is mounted at a height position where its bottom edge is positioned to be higher than the lowest part of the table base 1 when it is put into a most contracted state.