A carbapenem compound represented by a following formula [1], wherein R1 is C1 to C3 alkyl or C1 to C3 alkyl substituted by hydroxy. R is hydrogen atom or a group which regenerates a carboxyl group by hydrolysis in a living body, A is a following formula [1a], wherein E is a 5 to 7 membered cyclic ring optionally containing 1 to 3 hetero atoms (excluding benzene ring) which forms a bicyclic ring in corporation with the benzene ring, Y is hydrogen atom, C1 to C4 alkyl, C1 to C4 alkoxy, trifluoromethoxy, halogen atom or cyano group, or its pharmaceutically acceptable salt.