To obtain both a new polymer and a luminescent element which contains the polymer and has high luminance emission and high luminous efficiency and excellent durability.

The polymer is represented by the formula (1) (Am)p-(Bn)q-(Ck)r (A is a monomer unit containing pyrrole, thiophene, furan and its aromatic and heteroaromatic condensed ring derivatives; B is a monomer unit containing a heterocyclic derivative containing two or more hetero atoms on one ring system; C is a monomer unit containing a structure except those of B and C; (m) and (n) are each an integer of ≥1; (k) is an integer of ≥0; (p) and (q) are each a mol fraction (%) and are each 1-99; (r) is 0-98(%), p+q+5=100(%); at least one monomer unit of A, B and C is substituted with a ≥4C ballast group).