Hydroxyapatite (HAP, Ca₁₀(PO₄)₆(OH)₂) is a major component of bones and teeth and requires a specific crystal orientation for biomaterial applications. We have developed a method to control the orientation by applying a strong magnetic field during colloidal processing. In this study, we have demonstrated that suspensions with dispersed agglomeration-free nano particles can be produced by beads-milling HAP particles with zirconia beads as small as 0.05 mm. By slip casting in a high magnetic field and sintering using suspensions with dispersed agglomeration-free nano particles, high-density and oriented sintered bodies were successfully fabricated at low temperatures.