The present invention relates to underwear for men. An objective of the present invention is to provide underwear for men which separates a penis from a scrotum to completely separate the surface of the penis from the scrotum, isolates the scrotum from inner side of a thigh to avoid a direct contact between the scrotum and the inner side of the thigh, and exposes the scrotum to the air to suspend the scrotum in the air to maximize ventilation on the outer surface of the scrotum to effectively cool the scrotum and the testicles in the scrotum. To achieve the objective, the underwear for men comprises: a first fiber member to erect an entire penis in an opposite direction of a scrotum to separate the entire penis from the scrotum; a pair of second fiber members extended towards the outside of both sides of the first fiber member facing each other to isolate the scrotum and inner sides of thighs from each other; a space unit formed below the first fiber member between the second fiber members to allow the scrotum to completely protrude in the air; and a first stretchable strap formed on the lower end of the first fiber member brought into contact with the space unit to prevent the penis from leaning towards the scrotum.
