To provide a polyhedric material body freely joined to each other, which is obtained by freely joining plural polyhedrons to each other to form an optional form in a body, by compressing the plural polyhedrons.

Concerning this polyhedric material body, recesses and projections are formed at each face of each polyhedron symmetrical with respect to the center O of a sphere inscribed in a circumscribed sphere and many of the polyhedrons are compressed to join the recess and projections at each face to integrate the many polyhedrons to form an optional form in the state of freely joined to each other. An optional form which is never formed by toys such as conventional blocks can be formed to be very useful for improving the creative force of children. In addition, at the time of using this body as concrete aggregate, a remarkable effect is obtained for suppressing the rack of concrete due to the mutual joint of the aggregate.