A waterproof case for a switch that prevents the invasion of water drops inside the case of the switch. The waterproof case is comprised of an upper case 1 having holes 1g and 1h on a side thereof, and a lower case 25 having projected portions 25a and 25b on a side thereof that fit into the holes 1g and 1h on the side of the upper case 1. The upper case 1 has ribs 1i and 1j surrounding the holes 1g and 1h that guide water drops, which flow from the upper portion to the side of the upper case 1, in the downward direction. Thus, a waterproof case is provided that has ribs surrounding the holes on the side of the upper case so that the ribs 1i and 1j prevent water drops from entering into the case through the holes 1g and 1h.