An electro-optic polymer (EO polymer) comprising an electro-optic molecule (EO molecule) and a base polymer, the EO molecule having a structure in which a π-electron donor and a π-electron acceptor are conjugated via a π-conjugation bridge, the EO polymer having an electro-optic coefficient (EO coefficient) of 30 pm/V or more and a figure of merit of 10 × 10 -6 cm/dBV or more in an entire optical communication wavelength range of 1260 nm to 1625 nm, the FOM being defined by the following formula: FOM = n 3 r a max λ wherein n indicates a refractive index, r indicates an EO coefficient, α max indicates a maximum absorption coefficient in a wavelength range of interest, and λ indicates a wavelength; wherein the EO molecule is a compound represented by the following formula: wherein R D 1a, R D 23, and R D 3a independently represent a hydrogen atom, an alkyl group, an alkoxy group, an aryloxy group, an aralkyloxy group, a silyloxy group, an alkenyloxy group, an alkynyloxy group, a hydroxy group, -R 1 -OH (wherein R 1 is a hydrocarbon group), -OR 2 -OH (wherein R 2 is a hydrocarbon group), -OC (=O) R 3 (wherein R 3 is a hydrocarbon group), an amino group, -R 4 -NH 2 (wherein R 4 is a hydrocarbon group), a thiol group, -R 5 -SH (wherein R 5 is a hydrocarbon group), -NCO, or -R 6 -NCO (wherein R 6 is a hydrocarbon group), and R D 1a, R D 2a, and R D 3a each may have one or more identical or different substituents; R D 4a and R D 5a independently represent a hydrogen atom, an alkyl group, a haloalkyl group, an acyloxyalkyl group, a silyloxyalkyl group, -R 1 -OH (wherein R 1 is a hydrocarbon group), -R 4 NH 2 (wherein R 4 is a hydrocarbon group), an aryl group, -R 5 -SH (wherein R 5 is a hydrocarbon group), or -R 6 -NCO (wherein R 6 is a hydrocarbon group), and R D 4a and R D 5a each may have one or more identical or different substituents; X represents a linking group; and R A 1a and R A 2a independently represent a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, a cycloalkenyl group, an alkoxy group, an aryl group, a hydroxy group, -R 1 -OH (wherein R 1 is a hydrocarbon group), -OR 2 -OH (wherein R 2 is a hydrocarbon group), an amino group, -R 4 -NH 2 (wherein R 4 is a hydrocarbon group), a thiol group, -R 5 -SH (wherein R 5 is a hydrocarbon group), -NCO, or -R 6 -NCO (wherein R 6 is a hydrocarbon group), and R A 1a and R A 2a each may have one or more identical or different substituents. the EO polymer having an electro-optic coefficient (EO coefficient) of 30 pm/V or more and a figure of merit of 10 × 10 -6 cm/dBV or more in an entire optical communication wavelength range of 1260 nm to 1625 nm, the FOM being defined by the following formula: FOM = n 3 r a max λ wherein n indicates a refractive index, r indicates an EO coefficient, α max indicates a maximum absorption coefficient in a wavelength range of interest, and λ indicates a wavelength; wherein the EO molecule is a compound represented by the following formula: wherein R D 1a, R D 23, and R D 3a independently represent a hydrogen atom, an alkyl group, an alkoxy group, an aryloxy group, an aralkyloxy group, a silyloxy group, an alkenyloxy group, an alkynyloxy group, a hydroxy group, -R 1 -OH (wherein R 1 is a hydrocarbon group), -OR 2 -OH (wherein R 2 is a hydrocarbon group), -OC (=O) R 3 (wherein R 3 is a hydrocarbon group), an amino group, -R 4 -NH 2 (wherein R 4 is a hydrocarbon group), a thiol group, -R 5 -SH (wherein R 5 is a hydrocarbon group), -NCO, or -R 6 -NCO (wherein R 6 is a hydrocarbon group), and R D 1a, R D 2a, and R D 3a each may have one or more identical or different substituents; R D 4a and R D 5a independently represent a hydrogen atom, an alkyl group, a haloalkyl group, an acyloxyalkyl group, a silyloxyalkyl group, -R 1 -OH (wherein R 1 is a hydrocarbon group), -R 4 NH 2 (wherein R 4 is a hydrocarbon group), an aryl group, -R 5 -SH (wherein R 5 is a hydrocarbon group), or -R 6 -NCO (wherein R 6 is a hydrocarbon group), and R D 4a and R D 5a each may have one or more identical or different substituents; X represents a linking group; and R A 1a and R A 2a independently represent a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, a cycloalkenyl group, an alkoxy group, an aryl group, a hydroxy group, -R 1 -OH (wherein R 1 is a hydrocarbon group), -OR 2 -OH (wherein R 2 is a hydrocarbon group), an amino group, -R 4 -NH 2 (wherein R 4 is a hydrocarbon group), a thiol group, -R 5 -SH (wherein R 5 is a hydrocarbon group), -NCO, or -R 6 -NCO (wherein R 6 is a hydrocarbon group), and R A 1a and R A 2a each may have one or more identical or different substituents.