PURPOSE: To close a section circular hole even if the inner diameter of the section circular hole differs and to measure the volume of space formed in the section circular hole.

CONSTITUTION: A lower surface slide groove 1016 is provided at a lower surface fixing tool 1014 and a rotary tool 1013 is supported so that it can be rotated on the lower surface fixing tool 1014. An annular elastic body 1011 is provided outside the rotary tool 1013, an upper surface fixing tool 1012 is provided on the annular elastic body 1011, a plate-fixing hole 1017 is provided at the rotary tool 1013, an upper surface slide groove 1015 is provided at the upper surface fixing tool 1012, and the outside of a plurality of deformation actuation plates 1010 consisting of a plate-shaped rigid body is mounted to the annular elastic body 1011. A plate slide pin 1018 and a plate-fixing pin 1019 are provided at the deformation actuation plate 1010, the plate slide pin 1018 is inserted into the upper surface slide groove 1015 and a lower slide groove 1016, the plate- fixing pin 1019 is inserted into the plate-fixing hole 1017, and then the deformation actuation plate 1010 is laid out radially.