Abstract: Novel cephem compounds represented by a formula [I] and pharmacologically admissible salts or capable of physiologically hydrolyzable nontoxic esters thereof are disclosed. ##STR1## [wherein R.sup.1 indicates a straight-chain or branched lower alkyl group, which may be substituted by carboxyl group which may be protected, trityl group, hydrogen atom or fluorine-substituted lower alkyl group, R.sup.2 indicates a hydrogen atom, metal atom, protective group for carboxyl group or ester residue producible hydrolyzable ester in vivo, R.sup.3, R.sup.4, R.sup.5 and R.sup.6, which may be identical or different, indicate hydrogen atoms, halogen atoms, straight-chain or branched lower alkyl groups, which may be substituted, mercapto groups, which may be substituted, lower alkylamino groups, hydroxyl groups, which may be protected, lower alkoxy groups, lower alkanoyl groups, lower alkoxycarbonyl groups, or lower alkylenedioxy groups, which may be substituted, being maybe formed with R.sup.3 and R.sup.4, R.sup.