To provide a positive resist composition which exhibits high sensitivity, ensures no substrate dependency, and excels in profile configuration even when a basic substrate is used, and a pattern forming method using the positive resist composition.

The chemically amplified positive resist composition contains a compound (N) having at least one diazo group and at least one group which decomposes under the action of an acid to thereby generate an alkali-soluble group. The pattern forming method using the positive resist composition is also provided.