A bone substitute (a material for repairing biological tissues) made from .beta.-TCP as the raw material comprises a plate-type base member on the surface of which a plurality of grooves extending in a single direction are formed and separated from each other by partition wall members having an almost uniform thickness. This material sustains a sufficient binding force after application to a biological tissue and exhibits an excellent effect of forming a biological tissue. This bone substitute (material for repairing biological tissues) having a main body provided with a plurality of grooves extending in a single direction which are separated from each other by partition wall members having an almost uniform thickness, and a biodegradable viscous member which is filled into at least one of the penetrating holes of the main body, and contains an agonistic factor capable of increasing the cell activity, can provide agonistic factors of sufficient types and amounts to a biological tissue, and can control the sustained-release dose thereof.