Provided is an electrophotographic photosensitive member including a support, an undercoat layer formed on the support, and a photosensitive layer formed on the undercoat layer, in which the undercoat layer contains a polymer of a composition containing a compound represented by the formula (1). ##STR00001##

An electrophotographic photoreceptor includes a conductive substrate, an undercoat layer that is provided on the conductive substrate, and a photosensitive layer provided on the undercoat layer, in which the undercoat layer contains a binder resin and an electron transport material having a crystal density of 1.62 g/cm.sup.3 or greater, and a full width at half maximum (FWHM) of a maximum intensity peak in an X-ray diffraction spectrum measured in a thickness direction is 5.0 or less.

An electrophotographic photosensitive member includes a support, an undercoat layer formed directly on the support, and a photosensitive layer formed on the undercoat layer, wherein when an ionization potential of the undercoat layer is represented by IPu, the IPu is 6.0 eV or higher, when an ionization potential of the support is represented by IPs, the IPs is lower than the IPu, the undercoat layer contains a compound (), when an ionization potential of the compound () is represented by IP, the IP is 5.0 eV or higher and 5.4 eV or lower, and the IPs and the IP satisfy the following relational expression (1):

[00001]$\begin{array}{cc}\mathrm{IPs}\mathrm{IP}-1..& \left(1\right)\end{array}$

An electrophotographic photoreceptor includes a conductive support; and an undercoat layer and a photosensitive layer stacked on the conductive support, in which the undercoat layer contains crystalline electron transport compound particles. In X-ray diffraction measurement performed on the undercoat layer in a thickness direction, a maximum intensity peak has a half-width of 5 or less, and a maximum value Nmax among orientation indices N expressed by equation (1) below is 1 or more and 3 or less: $\begin{array}{cc}\mathrm{Orientation}\mathrm{index}=\frac{\frac{I_1}{.Math.I_1}}{\frac{I_2}{.Math.I_2}}& \left(1\right)\end{array}$ where I.sub.1 represents a relative integral intensity of each of peaks in the X-ray diffraction measurement performed on the undercoat layer in the thickness direction, and I.sub.2 represents a relative integral intensity of each of peaks in X-ray diffraction measurement performed on the undercoat layer processed into a powder form having a volume-average particle diameter of 5m or less.