PURPOSE: To produce a composition having remarkably improved physical properities such as tensile strength, flexural strength, etc. and improved heat-deformation temperature and moldability, and capable of forming an ultra-high precision part, by compounding a xylylenediamine polyamide resin, nylon 66 and potassium titanate single crystal fibers.

CONSTITUTION: The objective composition is produced by compounding (A) 55W90(wt)% xylylenediamine polyamide resin, (B) 5W15% nylon 66 and (C) 5W 40% potassium titanate single crystal fibers. The component C has an average fiber diameter of ≤1μ, average fiber length of 5W100μ, and a ratio of average fiber length to average fiber diameter of ≥10, and is preferably treated with 0.3W5% surface-treatment agent (epoxysilane or aminosilane coupling agent), based on the weight of the fiber.