Abstract: A biological implant is implantable in a base being a part of a living organism. The implant includes an implant body including at least an outer circumferential surface containing a titanium alloy. The implant body is implantable in the base. Based on a first curve indicating a profile of the surface of the implant body obtained with a measurement length of 25.4 µm and a second curve obtained by removing a long-wavelength component from the first curve at a cutoff value of 5 µm in image processing performed on an image of a cut surface of the implant body perpendicular to the outer circumferential surface of the implant body, an arithmetic mean roughness value as a surface roughness value Ra of the outer circumferential surface calculated using the second curve is greater than or equal to 0.2 µM.