A serial printer includes a print head movable along a print line of a recording sheet. A flexible carrier cable is attached to the print head for supplying a drive signal thereto. One end of the carrier cable is fixed to the movable print head, but its longitudinally intermediate portion is free, and bent to form a C-shape which follows the movement of the print head. The carrier cable includes a magnetic material, and a magnetic plate is provided at a position opposing the lower part of the C-shaped carrier cable to attract and hold the lower part of the carrier cable, whereby the vibration caused in the carrier cable by the movement of the print head is reduced.