To obtain a specific new cephem compound having 7- aminopyrazolo[1,5-a]pyridinium-4-ylmethyl group, etc., at the 3-site of cephem nucleus and exhibiting excellent antibacterial action even on a bacterial strain of the genus Pseudomonas.

This new cephem compound is expressed by formula I [R1 is H or an amino-protecting group; R2 is H, a lower alkyl or fluoromethyl; R3 is H, a lower alkyl or a (protected) carboxyl; R4 is H or a lower alkyl; R5 is H, an anion or a carboxyl-protecting group; A is methylene or propenylene; X is an anion; Q is N or methine; the wavy line is a bond of anti or syn configuration]. It has excellent antibacterial power and is useful, e.g. as an antibacterial agent exhibiting excellent antibacterial effect even on a bacterial strain of the genus Pseudomonas. The compound can be produced by reacting a new compound expressed by formula II with a cephem compound expressed by formula III (Z is a quaternary ammonium salt expressed by formula IV).