A natural garden is planned based on a new idea of the Third Ecology, namely, that of the construction of new natural conditions, The essencial factors indispensable for as many species as possible to complete their life cycles are collectively given in the relatively narrow planning area. An environment in which rich biofactors are established in conditions of dynamic ecological stability is expected. Among various structures build in this garden, a cottage-like structure to which a number of holes and crevices of various size are given as shelters and breeding sites for small animals including birds and insects may be very effective to the accumulation of species in this garden.