The present invention relates to a negative photoresist composition and a patterning method for device in which a photoresist pattern having a high sensitivity with a good reverse taper profile can be formed not only to realize an effective patterning of various thin films but also to facilitate removal of the photoresist pattern after the patterning. The photoresist composition comprises an alkali-soluble binder resin; a halogen-containing first photo-acid generator; a triazine-based second photo-acid generator; a cross-linking agent having an alkoxy structure; and a solvent.