PURPOSE: To aim at making units for a continuous wall rectilinear by providing chain-driven type excavating blades in the vicinity of the lower ends of kneading spindles in a kneading auger machine at a right angle to the spindles.

CONSTITUTION: Kneading spindles 5A through 5C are supported so as to be rotated clockwise and counterclockwise by multispindle devices 4 while they being held at predetermined intervals by means of coupling devices 7 which also serves as bearings for the spindles 5A through 5C. Further, driven sprockets 10, 11 and drive sprockets 12 are provided directly above and below the coupling devices 17. Further, excavating blades 16 are arranged at suitable positions in the vicinity of the lower ends of the kneading spindles 5A through 5C while the bosses of the driven sprockets 10, 11 are supported rotatably to kneading spindles 5A, 5B, respectively, through the intermediary of metals 3 while the boss of the drive sprocket 12 being fixed to the kneading spindle 5C by use of a key 14. With this arrangement, it is possible to increase the distance between the kneading spindles.