The present invention relates to an erection assisting device comprising: an expansion liquid accommodating pack disposed between the abdominal wall muscle of a user and subcutaneous fat, and accommodating an expansion liquid a pair of expansion-type intra-penis substitutive materials inserted in the penis of the user to cause erection a valve unit inserted in the top scrotum of the user, and controlling the supply and discharge of the expansion liquid from the expansion liquid accommodating pack to the expansion-type intra-penis substitutive materials a first connection line for connecting the expansion liquid accommodating pack with the valve unit and a second connection line for connecting the valve unit with the expansion-type intra-penis substitutive materials. The valve unit comprises: a valve body having a flow path for making the expansion liquid flow, and having an inlet connected with the first connection line, and having an outlet connected with the second connection line a control ball moving on the flow path, and opening and closing the inlet and the outlet a supply switch disposed to be longitudinally moved by external force applied by a user to an outlet side of the valve body, and controlling the supply of the expansion liquid from the valve body to the expansion-type intra-penis substitutive materials and a returning switch disposed to be longitudinally moved by external force applied by the user to an inlet side of the valve body, and controlling that the expansion liquid supplied to the expansion-type intra-penis substitutive materials returns to the expansion liquid accommodating pack through the inlet.COPYRIGHT KIPO 2017본 발명은 발기보조기구에 관한 것으로서, 사용자의 복벽근육과 피하지방 사이에 배치되며, 팽창액이 수용되는 팽창액수용팩과 사용자의 음경 내부에 삽입되어 발기를 일으키는 한 쌍의 팽창식음경내대용물과 사용자의 상부음낭 내부에 삽입되며 상기 팽창액수용팩으로부터 상기 팽창식음경내대용물로의 상기 팽창액의 공급과 배출을 제어하는 밸브부와 상기 팽창액수용팩과 상기 밸브부를 연결하는 제1연결라인과 상기 밸브부와 상기 팽창식음경내대용물를 연결하는 제2연결라인을 포함하며, 상기 밸브부는, 상기 팽창액이 유동되는 유로가 형성되며 상기 제1연결라인과 연결되는 유입구와 상기 제2연결라인과 연결되는 배출구를 갖는