To provide a sanitary underwear enabling the prevention of friction and sticking of the groin, the keeping and protection of clean groin, and the prevention of the exposure to other person's eyes by wearing a pair of trunks.

A deep cradle-shaped bag 6 is attached downward on a deformed elliptic wire 3 wrapped with a cushioning material 4. This is placed below and at the inside of the opening of a pair of trunks. The whole of the testicles can be comfortably kept in both sides of the boundary 8 at the center of the lowest part. The penis can be kept naturally owing to the constriction 7 of the wire.