The invention provides a delaying device (10) for release elements (12) of electrical circuit breakers, which is essentially constituted, in a circuit breaker structure (11), by at least a coil connected in series to a main circuit of a circuit breaker, said at least one coil actuating, when electrical power is supplied to it, at least an elastically-swinging lever (31) capable of rotating a release shaft (14) causing the tripping of said circuit breaker, said shaft being provided with at least one tongue (16) suitable to engage said at least one lever, characterized in that said delaying device is constituted by first delaying lever means elastically mounted on said release shaft, and acting on second delaying means of the delaying-mass type (19, 23), fastened onto said circuit breaker structure in correspondence of said first delaying lever means.