Abstract: An apparatus for facilitating the contact between solid particles and a fluid, which apparatus comprises a multi-layered network structure composed of a plurality of network structures consisting of a plurality of square nets of equal size held at regular intervals by means of spacers extending parallel to the nets separate fluid flow, said spacers concurrently forming plural elongated compartments with rectangular cross-section in conjunction with two adjacent nets, a bottom member placed at the lower ends of said nets alternately between two adjacent nets and edge holders for said nets as fixed parallel to said spacers, a housing to accommodate said multi-layered network structure and solid particles packed in said compartments of alternate layers of the multi-layered network structure; thereby a fluid being passed through fluid flow passages formed as alternate layers between said packed layers contacts solid particles.