To provide new cepham compounds having antimicrobial activities, their production method, intermediates and a pharmaceutical composition containing the cepham compounds.

The antibacterial compounds are expressed by formula I [in the formula W is CH or N; V is CH or N-O; R1 is H or an ester residue; R2 is a specific substituent such as -O-Y; and R3 is H, an acyl, a carboxy or other specific substituent].