A swing training device includes an axial hole and a gap communicated with the axial hole. A diameter of the axial hole is greater than or equal to a diameter of the neck of the head of the golf club. A width of the gap is greater than a diameter of the shaft of the club at a portion adjacent to the head, and the diameter of the neck is greater than the width of the gap. To mount the device of the present invention on a golf club, the device is fitted to the shaft via the gap, and then is moved downwards to be engaged with the neck of the head firmly.
