To provide a vehicular undercover for advantageously preventing the hang-down of an outer peripheral portion of a cover body mounted with a sound absorbing material, in a mounted state under a vehicle floor.

An engaging hole 44 is provided in the outer peripheral portion 42 of the cover body 12 with which the sound absorbing material 14 is overlapped, corresponding to a through-hole 21 of the sound absorbing material 14. A reinforcing plate part 46 with an engaging portion 58 is hinged thereto for reinforcing the outer peripheral portion 42 in such an overlapped structure that it is bent to be overlapped with the outer peripheral portion 42 of the cover body 12 while holding the sound absorbing material 14 therebetween. By bending the reinforcing plate part 46, the engaging portion 58 is inserted through the through-hole 21 to engage with the engaging hole 44. Thus, the sound absorbing material 14 is mounted on the cover body 12.