Provided is a body cavity access tool (1), comprising a retractor (5), a funnel-shaped instrument introduction part (6), and a closing part (7). The retractor (5) further comprises an inner-side ring-shaped member (9) which is to be positioned within a body cavity (3), and an outer-side ring-shaped member (10) which is to be positioned outside the body. Both members (9, 10) are coupled with a flexible cylindrical retraction member (11). The retraction member (11) passes through a body wall (2). The instrument introduction part (6) is inserted in the retractor (5). The closing part (7) is mounted on the outer-side ring-shaped member (10). The closing part further comprises an insertion part (21). The instrument is to be inserted in the body cavity (3), passing through the insertion part (21) and the instrument introduction part (6). A handle member (8) is positioned outside the body and within the retractor (5). The handle member (8) and the inner-side ring-shaped member (9) are coupled with a thread-shaped member (T). After an operation, it is possible, by pulling upward on the handle member (8), to remove the inner-side ring-shaped member (9) from the body cavity (3).
