A pattern forming method includes forming a resist film having a first region, a second region, and a third region, on a substrate, irradiating the first region with light or an energy ray in a first irradiation amount, and irradiating the second region with light or an energy ray in a second irradiation amount, the second irradiation amount being smaller than the first irradiation amount. The pattern forming method also includes dissolving the resist film of the first region by using first liquid, forming a coating film on a side surface of the resist film after the resist film of the first region is dissolved, and dissolving the third region by using second liquid that is different from the first liquid.