For stably forming a high-precision fine pattern and thereby producing a highly integrated electronic device with high precision, a resist composition for negative tone development, which can reduce the line edge roughness and enhance the in-plane uniformity of the pattern dimension and furthermore, can ensure excellent bridge margin, and a pattern forming method using the same are provided.A resist composition for negative tone development, comprising (A) a resin capable of increasing the polarity by the action of an acid to increase the solubility in a positive tone developer and decrease the solubility in a negative tone developer, (B) a compound capable of generating an acid upon irradiation with an actinic ray or radiation, and (C) a solvent, wherein the log P value of the acid generated from the (B) compound capable of generating an acid upon irradiation with an actinic ray or radiation is from 1.5 to 12.0; and a pattern forming method using the same.