A polyhydroxyalkanoate is disclosed which has in the molecule a unit represented by Chemical Formula (1). wherein R is arbitrarily selected from a hydrogen atom, a halogen atom, CN, NO 2 , COOR', SO 2 R", CH 3 , C 2 H 5 , C 3 H 7 , C(CH 3 ) 2 H and C(CH 3 ) 3 ; where R' is H, Na, K, CH 3 or C 2 H 5 , and R" is OH, ONa, OK, a halogen atom, OCH 3 or OC 2 H 5 ; and x is an integer arbitrarily selected from 1 to 8; with the proviso that a polyhydroxyalkanoate is excluded which has a hydrogen atom as R and x in all the units is 2 or 4. Also disclosed is 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.