A polyhydroxyalkanoate characterized by having in the molecule a unit represented by Chemical Formula (1): ##STR1##

wherein n may assume any one integral value within the range of from 1 to 8. Also disclosed are a process for producing the polyhydroxyalkanoate by the use of a microorganism having the ability to produce the polyhydroxyalkanoate and accumulate it in the bacterial body; a charge control agent, a toner binder and a toner which contain this polyhydroxyalkanoate; and an image-forming method and an image-forming apparatus which make use of the toner.