The present invention provides a novel acid addition salt of 1-(5-(2,4-difluorophenyl)- 1 -((3 -fluorophenyl)sulfonyl)-4-methoxy- 1 H-pyrrol-3 -yl)-N-memylmethanarnine. The above- described acid addition salt can have not only excellent proton pump inhibitory activity, gastric damage inhibitory activity and defensive factor-enhancing effect, but also excellent eradication activity against