Electromagnetic wave absorption material and electromagnetic wave absorber

An electromagnetic wave absorber, comprising:

• a plurality of electromagnetic wave absorption layers each including fibrous carbon nanostructures and an insulating material,
• wherein fibrous carbon nanostructures and/or insulating materials included in the respective plurality of electromagnetic wave absorption layers are of a same type or different types,
• the plurality of electromagnetic wave absorption layers are denoted as a first electromagnetic wave absorption layer, a second electromagnetic wave absorption layer, . . . , and an nth electromagnetic wave absorption layer from a side farther from an electromagnetic wave incidence side,
• contents of the fibrous carbon nanostructures in the respective plurality of electromagnetic wave absorption layers are denoted as A1 parts by mass, A2 parts by mass, . . . , and An parts by mass where a content of the insulating material in a corresponding electromagnetic wave absorption layer is 100 parts by mass, and
• the following condition (1-2) and condition (2) or (3) hold true:
• 0.3≤A1≤0.8, wherein the fibrous carbon nanostructures are fibrous carbon nanostructures that exhibit a convex upward shape in a t-plot obtained from an adsorption isotherm and have BET specific surface area of 800 m2/g or more (1-2)
• A1>A2,when n is 2 (2)
• A1>A2≥ . . . ≥An,when n is a natural number of 3 or more (3), and
• the first electromagnetic wave absorption layer from among all of the plurality of electromagnetic wave absorption layers has a highest content of fibrous carbon nanostructures.