Provided is an electrochemical display element composed of a simple member structure, capable of driving at low voltage, and exhibiting high display contrast and white display reflectance, and further to provide the electrochemical display element exhibiting reduced variation in reflectance during repetitive driving even after storage for a long duration. Disclosed is an electrochemical display element possessing an N-oxyl derivative represented by the following Formula (1), an electrolyte and a pair of facing electrodes: wherein each of R1, R2, R3 and R4 independently represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group or a heterocyclic group, which may have a hydrogen atom or a substituent; Z1 represents a group of atoms having 2 or 3 atoms to form a cyclic structure; and Z1 may also have a substituent.