Abstract: An installation method of panels includes a step of assembling panels by fitting projection parts 2, 3 of one panel 1 to insertion grooves 5, 6 of another panel 1, and a step of elastically attaching panels by applying an elastic tensioning force between assembled of panels. Also, a rail type fixing apparatus for installing panels includes a rail 20 having a guide groove 21 formed in a longitudinal direction thereof, and a plurality of attachment panels which are guided along guide groove 21 and are provided movably in the longitudinal direction of the rail 20 and in which a hook projections 32 are provided, and an elastic member which is provided between adjacent attachment panels and applies a tension restoring force between hook projections of the attachment panels to draw the hook projections 32 of the respective attachment panels 30 to each other.