Abstract: A mattress having a three-dimensional elastic structure of the present invention has a structure in which a main elastic body independently contracts and expands by multiple first to fourth auxiliary elastic slits which intersect with each other in left and right directions, front and rear directions, and up and down directions so as to form a three-dimensional air tunnel. Accordingly, when the first to fourth auxiliary elastic slits contract and expand, air is discharged in all directions of the main elastic body through the three-dimensional air tunnel so as to disperse the pressure by a human body, thereby inducing good blood circulation, and heat is released through the three-dimensional air tunnel so as to secure air permeability, thereby inducing maintenance of a proper sleep temperature so as to provide a more comfortable sleep environment.