Variation in fiber diameter and wall thickness was analyzed, with respect to the distance from xylem vessels in tangential and radial directions, using images containing the largest diameter along individual fibers from serial sections. For the diameter of the fibers around the vessel, it was often difficult to make a measurement in the radial and tangential direction, because of deformation. Then, around a vessel, we measured the fiber lumen diameter along the radial and tangential axes of the adjacent vessel. These are respectively referred as direction perpendicular to vessel enlargement (PnVE) and parallel with vessel enlargement (PrVE), as the enlarging vessel apparently accounts for the directionality of this fiber deformation. The change in cell wall thickness of individual fibers was also measured from the serial cross sections. Fibers adjacent to vessels were significantly wider in diameter and had thicker cell walls in the PrVE than those that were more distant from vessels in both radial and tangential directions. Wall thickness along the fiber length was found to vary in both fibers adjacent to and distant from the vessel, whereby wall thickness was greatest at the center, and gradually decreased towards the tip of the fiber.