base disk 101 and has first and second slopes 111 and 112 forming both of its sides and third fourth and fifth slopes 113 114 and 115 forming its outer top and inner edges the first and second slopes 111 and 112 have predetermined inclined angles with respect to vertical central planes of the agitating blades 102 the fourth slope 114 is located at a middle portion of the upper edge of the agitating blade 102 and is slightly inclined down to the outside the third and fifth slopes 113 and 115 are inclined down to the outside and inside respectively and have predetermined inclined angles the agitating post 110 is constructed such that its center is eccentrically positioned from the rotating center 34 o 34 of the pulsator 100 by a predetermined distance 34 l 34 and its upper surface 121 has a rectangular or elliptic shape and a predetermined inclined angle a 0 u00b0 75 u00b0 in this embodiment the upper surface 121 is inclined down from the center of the post 110 to the rotating center of the agitator 100 the agitating post 110 is formed at its upper end with a coupling hole 122 such that the center of the coupling hole 122 is aligned with the center of the base disk 101 the coupling hole 122 is adapted to couple the pulsator 100 to a driving shaft not shown by means of coupling member inserted therein the base disk.