Provided is a penile erection assistance tool that can provide a ring body able to maintain a high degree of airtightness in a cylinder, can be easily interchanged, and feels good to use. This penile erection assistance tool is provided with: a cylindrical container having an insertion opening at one end and an air discharge opening at the other end； and a ring body configured so that an outer circumferential rim thereof is elastically and detachably fitted to the insertion opening of the container, and a central hole thereof is introduced into the container. The penis is inserted into the central hole of the ring body and the pressure in the container is reduced by suctioning the air therein out through the air discharge opening while the ring body is fitted around the root of the penis, thereby squeezing the penis, causing blood to pool therein and effecting an erection. The ring body is constituted by at least three layers of elastic members being stacked together, and is configured so that the elastic members are bonded to one another along the outer circumferential rim, the adjacent elastic members are separated from each other in the portion that is introduced into the container, and the elastic members that are adjacent at the tips thereof are in contact with each other.本發明提供一種陰莖勃起輔助器具，可提供能夠將圓筒的氣密性保持地高，並且轉移亦容易，且使用感亦良好的環狀體。本發明的陰莖勃起輔助器具包括：圓筒狀的容器，於一端設置插入口，於另一端設置排氣口；以及環狀體，以環狀體的外周緣彈性地且能夠裝卸地嵌合於容器的插入口上，環狀體的中心孔朝容器的內部突入的方式而構成。於將陰莖插入環狀體的中心孔中，並藉由環狀體來環抱陰莖的根部的狀態下，自排氣口抽吸容器的內部的空氣來進行減壓，藉此勒緊陰莖而充血並勃起。環狀體是使至少三層的彈性構件重疊來構成。彈性構件於外周緣上相互黏著並延伸，於朝容器內的突入部中鄰接的彈性構件為彼此隔離並延伸，於前端處鄰接的彈性構件為彼此相互接觸。
