An animal positioner, comprising: two forelimb positioning members (6a, 6b) each composed of a plate-like body made of an elastically-deformable soft synthetic resin, the two forelimb positioning members (6a, 6b) being cylindrically attached to right and left forelimbs (5a, 5b) of an animal, respectively, so as to wrap the right and left forelimbs (5a, 5b); two hindlimb positioning members (8a, 8b) each composed of a plate-like body, the two hindlimb positioning members (8a, 8b) being cylindrically attached to right and left hindlimbs (7a, 7b) of the animal, respectively, so as to wrap the right and left hindlimbs (7a, 7b), the two hindlimb positioning members (8a, 8b) being longer than the two forelimb positioning members (6a, 6b); a trunk positioning member composed of a plate-like body, the trunk positioning member being longer than the two hindlimb positioning members (8a, 8b) and being cylindrically attached to a trunk of the animal so as to wrap the trunk between the two forelimb positioning members (6a, 6b) which are attached to the right and left forelimbs (5a, 5b) of the animal, respectively, and the two hindlimb positioning members (8a, 8b) which are attached to the right and left hindlimbs (7a, 7b) thereof, respectively; and a head positioning member composed of a plate-like body made of an elastically-deformable soft synthetic resin, the head positioning member being attached to a head of the animal so as to form a truncated cone circumferential surface and wrap the head above the two forelimb positioning members (6a, 6b), characterized in that - the two forelimb positioning members (6a, 6b) are cylindrically attached to the right and to the left forelimbs (5a, 5b) of an animal in a stretched state, respectively, so as to wrap the right and left forelimbs (5a, 5b), - the two hindlimb positioning members (8a, 8b) being cylindrically attached to the right and to the left hindlimbs (7a, 7b) of the animal in a stretched state, respectively, so as to wrap the right and left hindlimbs (7a, 7b), - the plate-like bodies of which the two hindlimb positioning members (8a, 8b) are composed being made of an elastically-deformable soft synthetic resin, and - the plate-like body of which the trunk positioning member is composed being made of an elastically-deformable soft synthetic resin. two forelimb positioning members (6a, 6b) each composed of a plate-like body made of an elastically-deformable soft synthetic resin, the two forelimb positioning members (6a, 6b) being cylindrically attached to right and left forelimbs (5a, 5b) of an animal, respectively, so as to wrap the right and left forelimbs (5a, 5b); two hindlimb positioning members (8a, 8b) each composed of a plate-like body, the two hindlimb positioning members (8a, 8b) being cylindrically attached to right and left hindlimbs (7a, 7b) of the animal, respectively, so as to wrap the right and left hindlimbs (7a, 7b), the two hindlimb positioning members (8a, 8b) being longer than the two forelimb positioning members (6a, 6b); a trunk positioning member composed of a plate-like body, the trunk positioning member being longer than the two hindlimb positioning members (8a, 8b) and being cylindrically attached to a trunk of the animal so as to wrap the trunk between the two forelimb positioning members (6a, 6b) which are attached to the right and left forelimbs (5a, 5b) of the animal, respectively, and the two hindlimb positioning members (8a, 8b) which are attached to the right and left hindlimbs (7a, 7b) thereof, respectively; and a head positioning member composed of a plate-like body made of an elastically-deformable soft synthetic resin, the head positioning member being attached to a head of the animal so as to form a truncated cone circumferential surface and wrap the head above the two forelimb positioning members (6a, 6b), characterized in that - the two forelimb positioning members (6a, 6b) are cylindrically attached to the right and to the left forelimbs (5a, 5b) of an animal in a stretched state, respectively, so as to wrap the right and left forelimbs (5a, 5b), - the two hindlimb positioning members (8a, 8b) being cylindrically attached to the right and to the left hindlimbs (7a, 7b) of the animal in a stretched state, respectively, so as to wrap the right and left hindlimbs (7a, 7b), - the plate-like bodies of which the two hindlimb positioning members (8a, 8b) are composed being made of an elastically-deformable soft synthetic resin, and - the plate-like body of which the trunk positioning member is composed being made of an elastically-deformable soft synthetic resin. - the two forelimb positioning members (6a, 6b) are cylindrically attached to the right and to the left forelimbs (5a, 5b) of an animal in a stretched state, respectively, so as to wrap the right and left forelimbs (5a, 5b), - the two hindlimb positioning members (8a, 8b) being cylindrically attached to the right and to the left hindlimbs (7a, 7b) of the animal in a stretched state, respectively, so as to wrap the right and left hindlimbs (7a, 7b), - the plate-like bodies of which the two hindlimb positioning members (8a, 8b) are composed being made of an elastically-deformable soft synthetic resin, and - the plate-like body of which the trunk positioning member is composed being made of an elastically-deformable soft synthetic resin.