Vehicle interior illumination lamp

A vehicle interior illumination lamp comprising:

• a design panel including a light transmission portion in at least a part of a front surface side of the design panel, the light transmission portion being configured to transmit light;
• a light source configured to emit light toward the front surface side of the design panel;
• a reflector arranged at a position facing the light transmission portion of the design panel and configured to reflect light from the light source;
• a light guide prism including
• a light introduction portion arranged on the reflector at a side where the light source is positioned and configured to allow each of light from the light source and light reflected by the reflector to be incident on the light introduction portion, and
• a crescent-shaped prism main body configured to guide the light incident on the light introduction portion;
• and
• an emission prism arranged on the reflector so as to be adjacent to the crescent-shaped prism main body and configured to emit light guided through the crescent-shaped prism main body toward the light transmission portion of the design panel, wherein
• the crescent-shaped prism main body includes a plurality of second lens cuts arranged along a side surface of the crescent-shaped prism main body in a longitudinal direction of the crescent-shaped prism main body at a side of the reflector, and
• the plurality of second lens cuts are configured to refract light guided from the crescent-shaped prism main body toward the emission prism.