Derivatives of penicillanic acid sulfones are known to be irreversible inhibitors of $eta$-lactamase. Eight 6-tricyclic methylene penicillanic acid sulfones were prepared, and their $eta$-lactamase inhibitory activities were evaluated against $eta$-lactamase types I, II, III and IV. Among the tricycles attached to 6-exomethylenepenam sulfones, thiazolobenzimidazole(12a-12b), fluorene(12c), and carbazole(12e), showed inhibitory activity on type I, II and III $eta$-lactamase. But phenanthrene(12d), and anthracene(12f-12h) derivatives showed little $eta$-lactamase inhibitory activity. The synergic effects of the selected compound(l2b) in 1:4 combination with piperacillin showed some protection to piperacillin for the resistant strains of E. coli DC2 and P. aeruginosa 1771.