PURPOSE: To enable highly efficient and light nonuniformity uncausal illumination without causing any problem even if a mirror reflection plate having high reflectance is used by eliminating nonuniformity of light on a wall surface being an illumination object.

CONSTITUTION: A second reflecting plate part 5 is formed on an ellipse using a first intersection (b) and a second intersection (c) as a focus. A straight line is drawn so as to pass in a contact condition through the tip of a first reflecting plate part 4 and an upper side surface of a lamp 3, and an intersection at which this straight line and the ellipse cross each other above the lamp 3 is set as a third intersection (d), and the third intersection (d) is used as one end part of the second reflecting plate part 5. An intersection at which a line in the lowermost end direction of an illumination object passing through the first intersection (b) and the ellipse cross each other above the lamp 3 is set as a fourth intersection (e), and the fourth intersection (e) is used as the other end part of the second reflecting plate part 5.