Microscope illumination device and microscope

A microscope illumination device comprising:

• a white LED light source that includes a board, a plurality of LED chips that are arranged on the board and that each emit excitation light, and a phosphor layer that is provided so as to cover the plurality of LED chips and that includes at least three types of phosphors;
• and
• an illumination optical system that includes an aperture stop on a plane on which light from the white LED light source is condensed,
• wherein:
• the plurality of LED chips are arranged so as to be projected into an aperture of the aperture stop when the aperture stop is in a fully open state;
• and
• when MG is a magnification of an image of the white LED light source projected onto the plane on which the aperture stop is located, φAS is an aperture diameter of the aperture stop in the fully open state, φ2 is an aperture diameter of the aperture stop in a state in which an aperture size of the aperture stop is minimized, R is a diameter of a minimum circle including the plurality of LED chips, S1 is an area of one LED chip of the plurality of LED chips, and S0 is a sum of the areas of the plurality of LED chips, conditional expressions (4), (5), and (6) below are satisfied:
• 0.25≤(S1×MG)/(π×(φ2/2)2)≤1 (4);
• 0.1≤S0/(π×(R/2)2) (5);
• and
• 0.03≤(S0×MG)/(π×(φAS/2)2)≤0.15 (6).