PURPOSE: To simply adjust bundling timing and also not to deviate from it for a long period by connecting a controller outputting a signal for starting bundling operation at the bundling part to the driving part of the bundling part, basing a detected result of a detector which detects the string-feed posture of a needle feeding the bundling string to the bundling part.

CONSTITUTION: A controller 27 outputs a control signal to a driver 28 to carry out bundling operation in order to drive further a pulse motor 24, when the counted numbers of the pulse signal from the second encoder 25 coincide with or surpass the counted numbers of the pulse from the first encoder 21 at the time when the needle 5 reaches the uppermost point so that the bundling bill 7 and string holder 8 start operation at the time or when signals from a sensor 29 is input into the controller 27. In addition to the above, the pulse motor 24 is controlled for a bundling cam gear 9 after bundling so that a partial gear 26, the bundling bill 7 and the string holder 8 stop in an initial waiting posture, being apart with a specified angle against the axial center of the bundling drive shaft.