To bind firmy a plurality of petals sorted out by their weights and lengths by a flower sorter.

Two rotors 32 of left and right driven by a motor 34 are installed above a support 62 on which petal ends 4 are placed. A presser 44 connected with the rod 42 of a cylinder 41 is elastically supported by a spring 46. Rotors 32, by rotating downward, hold and press the petal ends 4 from left and right, and also lower the presser 44 to hold and compress the stems 4. In this condition, a binder arm is rotated around the stem ends to bind firmly with binding string.