A contact detection instrument including a rod, a tip sensor portion that is attached to one end of the rod and is inserted into a living body through a hole, a speaker that, from outside the living body, inputs a sound into a hollow space that is formed in the interior of the rod and the tip sensor portion, and a microphone that, outside the living body, outputs an electrical signal that corresponds to the sound inside the hollow space, with the tip sensor portion including an elastic material that covers the hollow space.