. . . "A cephalosporin compound of the formula (I): ##STR140## wherein X is a hydrogen atom, a chlorine atom, a methyl group, a methoxy group, an acetoxymethyl group or --CH2 SHet wherein Het is a 5-membered heterocyclic ring containing therein 1 to 4 nitrogen, oxygen or sulfur atoms; R1, R2 and R3 each independently is a hydrogen atom or a protective group which can be pharmaceutically hydrolyzed; and R" . . .