Radio wave absorber

A radio wave absorber comprising:

• hexagonal ferrite particles;
• and
• a holding material filled with the hexagonal ferrite particles,
• the hexagonal ferrite particles including
• first particles, and
• second particles that are larger than the first particles in particle size,
• the first particles each having a first particle size of 0.05 μm or more and less than 1 μm,
• the second particles each having a second particle size of 5 μm or more and 100 μm or less,
• the first particles including first single-domain particles,
• the second particles including second single-domain particles,
• a proportion of an area of the first single-domain particles and the second single-domain particles to an area of the hexagonal ferrite particles being 30 percent or more.