Disclosed is an excellent pharmaceutical product for treatment or prevention of hypertension and the like. Specifically disclosed is a specific acid addition salt of 2-amino-1,4-dihydro-6-methyl-4-(3-nitrophenyl)-3,5-pyridinedicarboxylic acid 3-(1-diphenylmethylazetidine-3-yl) ester 5-isopropyl ester, which is useful as a pharmaceutical product for treatment or prevention of hypertension and the like.