A waterproofing case with a first case and a second case includes a non-annular groove that has a start point side and an end point side and is arranged in parallel by a barrier rib of a certain length, in one of annular bonding portions. The waterproofing case also includes a cutout portion provided at a middle portion of the barrier rib so as to allow a groove portion at the start point side and the end point side to communicate with each other and a plastic elastomer that is disposed within the non-annular groove by curing after being coated. Furthermore, the waterproofing case includes a protrusion that bisects an exposed portion of the plastic elastomer disposed within the non-annular groove toward opposite walls of the non-annular groove at bonding two cases, in other annular bonding portion of the first case and the second case.