To provide fiber-based forming base material which is used as lining material for the interior of an automobile or the like and is low in density and lightweight and to provide a method for manufacturing it.

Foamed synthetic resin bead bodies 2 are included in fiber material 1 being main material. The body of forming base material is fused on the surfaces of the respective foamed synthetic resin bead bodies 2 to manufacture fiber-based forming base material consisting of a platelike forming body. Both the fiber-based forming base material and the forming material, in which numberless foamed synthetic resin bead bodies 2 are included between fiber materials being the main material, are sandwiched between air-permeable members and hot air is passed. The surfaces of the foamed synthetic resin bead bodies 2 are melted by this hot air. Thereafter, the fiber-based forming base material and the forming material are pressurized between the air- permeable members.