<p>A surgical instrument capable of inserting an interspinal spacer between adjacent spinous processes by a simple operation. The surgical instrument is inserted between the adjacent spinous processes for use and used to insert the tubular interspinal spacer with a hollow part between the spinous processes. The surgical instrument comprises an insert member having an insert part inserted into the hollow part of the interspinal spacer and a holding member holding the insert member. The surgical instrument is characterized in that, where one end part of the insert member is designated as a first end part and the other end part is designated as a second end part, the insert member is inserted into the hollow part of the interspinal spacer and a held part installed near the first end part of the insert member is used in the state of being held by the holding member. The insert member further comprises, at the second end part on the opposite side of the first end part, a support part for preventing the interspinal spacer from being fallen when the interspinal spacer is inserted into the insert part.</p>
