Disclosed herein are 7.beta.-[(Z)-2-(5-amino-1,2,4-thiadiazol-3-yl)-2-methoxyiminoacetamido]-3-(4-carbamoyl-1-quinuclidinio)methyl-3-cephem-4-carboxylate crystals comprising X-ray diffraction pattern possessing the characteristic diffraction intensity at the spacing d (unit: angstrom) shown in the following (i), (ii) or (iii):(i): 6.2, 5.1 and 5.0;(ii): 10.6, 5.3 and 5.1;(iii): 15.4, 5.0 and 4.6.A process for the preparation of the crystals is also disclosed.