To provide a filled culvert formation device capable of simultaneously carrying out manufacture and execution of a rock wool granulated hydrophobic material and solving troubles such as clogging.

The drawing or the self-propelling mixture filled culvert formation device for forming the filled culvert filled with a hydrophobic material consisting of a granulated mixture of the rock wool and an inorganic hydraulic material includes a ditch forming means for forming a ditch in a soil by travelling, a hydrophobic material filling means for filling the ditch with the hydrophobic material and a mixing means having a conveying function for conveying the granulated mixture regulated by stirring and mixing the rock wall and the inorganic hydraulic material to a discharge section, and it is so constituted that the hydrophobic filling means is continuously connected to the discharge section of the mixing means. The mixing means as a ribbon mixer is so regulated that a mounting angle of a stirring vane collects a mixing material on the discharge section, and the ribbon mixer capable of preventing the crush of the rock wool can be used.