Abstract: Disclosed is an excavating, sieving and grading device for a working crawler arranged such that each pair of first and second right and left legs 14, 14a and 17, 17a are vertically disposed to a bucket main body 7, the first right and left legs are connected to each other by a first reinforcing member 15, the second right and left legs are connected to each other by a second reinforcing member 18, and first and second guide rollers 16, 19 for supporting and guiding a first guide rail 21 disposed on the bottom surface of a movable frame 12 are provided on the first and second reinforcing members. With this arrangement, the movable frame provided with the sieve net is stably supported and guided to the bucket main body to thereby increase the strength of the excavating, sieving and grading device.