A tone generating apparatus comprising a first tone signal generator including the same number of oscillators as a polyphonic number each for generating a tone signal of that tone component of tone components constituting a musical tone which has a relatively long tone-ON time; a first assigner for assigning tone generation to one of the oscillators of the first tone signal generator; a second tone signal generator including oscillators each for generating a tone signal of a different one of the tone components constituting a musical tone than the tone component having a relatively long tone-ON time, a quantity of the oscillators being less than the polyphonic number; and a second assigner for assigning tone generation to one of the oscillators of the second tone signal generator, whereby when a tone generation is specified, a tone signal output from one of the oscillators of the first tone signal generator assigned by the first assigner and a tone signal output from one of the oscillators of the second tone signal generator assigned by the second assigner are synthesized to produce a tone signal.