A pattern forming method including a step of coating a substrate with an actinic ray-sensitive or radiation-sensitive resin composition and forming an actinic ray-sensitive or radiation-sensitive film; a step of simultaneously irradiating the actinic ray-sensitive or radiation-sensitive film with a plurality of electron beams; and a step of developing the actinic ray-sensitive or radiation-sensitive film after the irradiation with electron beams is provided. The composition contains a resin (A), a photoacid generator (B), and an acid diffusion control agent (C) and a molar ratio (Qp) between the photoacid generator (B) and the acid diffusion control agent (C), which is represented by Equation (1) is 0.3 or greater. Qp(molar ratio)=Acid diffusion control agent (C)/Photoacid generator (B)   (1)