Abstract: A smoke detector includes: a casing; a first light emitting unit; a second light emitting unit; and a light receiving unit. A second scattering angle that is an angle between the reception axis of the light receiving unit and a second extension extending from an intersection of the second emission axis and the reception axis in a direction away from the second light emitting unit is larger than a first scattering angle that is an angle between the reception axis of the light receiving unit and a first extension extending from an intersection of the first emission axis and the reception axis in a direction away from the first light emitting unit.

Abstract: A nerve stimulation electrode implantation system includes: an introduction portion that has a cylindrical main body which has an internal cavity, and an incision component which has a blunt dissection portion that bluntly dissects biological tissue, and which is formed so as to be transparent, and which is attached to a distal end portion of the main body; an observation portion that is inserted into the introduction portion such that it is able to observe the periphery of the incision component through the incision component; and a peeling portion that is positioned such that it is able to rotate around its own axis and is able to move relatively in this axial direction relative to the introduction portion, and that removes peripheral tissue from the periphery of the nerve tissue.

Abstract: An electrostimulation system includes an electrostimulation lead which has a connector connected to an electrostimulation device, a conducting wire pair electrically connected to the connector, and a sheathing body insulating the conducting wire pair, and is provided to pass through a vein, an electrostimulation block portion which is provided on the leading end side of the electrostimulation lead, and has an electrode portion electrically connected to the conducting wire pair and fixing hooks urging the electrode portion toward the inner wall of the vein, and a rotary member which has an engagement groove to be detachably engaged with the electrostimulation block portion and rotates the electrostimulation block portion placed in the vein around the center line of the vein through the engagement groove.