Light irradiation device

A light irradiation device comprising:

• a first reflective portion that is arranged at a concave inner surface formed so as to have a substantially arcuate shape and that permits a wire-like member to be inserted into an interior thereof;
• at least one light-emitting portion that emits light toward the wire-like member from a direction which is circumferential with respect to the wire-like member;
• and
• a second reflective portion that is planar;
• wherein at least a portion of the second reflective portion is arranged between an end of the first reflective portion and an end of the light-emitting portion in a direction circumferential with respect to the first reflective portion, and
• wherein a reflective surface of the second reflective portion is arranged perpendicular to an optical axis of the light emitted from the light-emitting portion.