Epoxy resin, epoxy resin composition, epoxy resin cured product and composite material

An epoxy resin, comprising an epoxy compound represented by the following Formula (1):

• wherein, in Formula (1), each of R1, R2 and R3 independently represents a monovalent group, at least one of the monovalent groups represented by R1, R2 and R3 includes a mesogenic structure, and at least one of the monovalent groups represented by R1, R2 and R3 has an epoxy group.

An epoxy compound having a main chain comprising two mesogenic structures and one branch, and having a ratio of area B to area A of 3% or more, wherein the area A is a total area of peaks derived from epoxy compounds having a main chain including two or more mesogenic structures, and the area B is an area of a peak derived from the epoxy compound, as shown in a chart obtained by gel permeation chromatography (GPC).

An epoxy resin composition, comprising an epoxy compound having a mesogenic structure and a curing agent, and having a value of η′4/η′3 equal to 3 or less, wherein η′3 is an initial dynamic shear viscosity (Pa·s) and η′4 is a maximum value of dynamic shear viscosity (Pa·s), in a measurement of dynamic shear viscosity.