Bacillus subtilis J105, high resistant bacteria against $eta$-lactam antibiotics, become higher resistant through induction of $eta$--lactamase in the presence of $eta$--lactam antibiotics. When there is no antibiotics in medium, the production of resistance-inductive $eta$--lactamase reached its plateau 15 hours later. But when there is ampicillin (500$mu extrm{g}$/$mell$) in medium, the production of enzyme reached its plateau 25 hours later since cultivating bacteria, whereas it is found that enzyme 2,900 units/$mell$ about 20 times as much as compared with not-presence of antibiotics was actived. In addition, as the result of MIC comparing applying ampicillin-treated and non-treated strain MIC of ampicillin-treated strain is about 2~27 times higher. It is considered that this strain induce $eta$--lactamase production by ampicil-lin-treatment, then increasing it resistance. It is found that this resistant strain induce $eta$--lactamase production against cephalosporin antibiotics as well as peni-cillin. As the result of examining the time of adding antibiotics for each phase of growth, it is concluded that logarith-mic phase is the most effective. As the aboves, it is suggested that this strain is a peculia strain that its resistance is induced high by various $eta$--lactam antibiotics.