Patent ID: 8256362

Claim:
An embroidery sewing machine comprising: a zigzag sewing head including: a needle bar reciprocatively drivable with a sewing needle attached thereto; a rotary member provided around an outer periphery of the needle bar for rotation about an axis of the needle bar; and a guide section for guiding a string-shaped embroidering material to a sewing position; a first calculation section for calculating, on the basis of sewing data, a sewing-progressing direction angle for rotating the rotary member to orient the embroidering material, guided by the guide section, in a sewing-progressing direction; and a second calculation section for adding or subtracting a zigzag-swinging angle to or from the sewing-progressing direction angle, calculated by said first calculation section, to thereby calculate a target rotational angle of the rotary member, wherein the rotary member is rotated in accordance with the target rotational angle calculated by said second calculation section.