An adsorption method adsorbs a substance by using a tube-shaped apatite crystal. The apatite crystal may be a monocrystal given by a general formula M25(PO4)3X (M2 denotes at least one element selected from the group consisting of divalent alkali earth metal and Eu, and X denotes at least one element or molecule selected from the group consisting of halogen element and OH). The outer form of the apatite crystal may be a hexagonal prism in which the aperture of a hole formed on a top surface or bottom surface of the hexagonal prism may be hexagonal.