An optical fiber alignment device includes an image-capturing device capturing images of end surfaces of two optical fibers; an image-analyzing device obtaining position coordinates of two or more cores in the end surfaces from the image captured by the image-capturing device for each of the two optical fibers; a calculation device substituting the position coordinates of the cores obtained for each of the optical fibers in a theoretical equation that represents a total sum of axial deviation losses at the time of splicing the cores to each other, the calculation device obtaining a positional relationship between the end surfaces of the optical fibers from the theoretical equation such that the total sum of the axial deviation losses becomes a minimum; and a driving device arranging the optical fibers such that the end surfaces of the optical fibers satisfy the positional relationship obtained by the calculation device.