A miniature electric sewing machine includes a shaft support bracket mounted on one side of a casing, a rotatable shaft supported on the shaft support bracket for rotation so as to extend in parallel with the side surface of the casing, a spindle support arm fixed to the rotatable shaft, and a bobbin winder spindle fixed to a distal end of the spindle support arm so as to extend in parallel with the rotatable shaft. The spindle support arm has a length of 35 mm or more. The spindle support arm fixed to the rotatable shaft assumes a position where it is normal to the side face of the casing or another position where the bobbin winder spindle fixed to the distal end of the arm is directed obliquely downwardly. A stopper is formed on the spindle support arm to be abutted against the side face of the casing when the arm is normal to the casing side face, preventing further upward rotating movement of the arm from the normal position. A large diameter bobbin is loosely fitted onto the bobbin winder spindle and subsequently, a rubber ring is attached to the spindle for preventing the bobbin from falling off.