To provide a coating film forming method for uniformly coating an optional substrate with an optional coating solution while finely controlling the film thickness abnormal part of an edge, for example, the position or height of an edge bead in order to realize necessary flatness.

In the coating film forming method for spreading and fixing the coating solution on a support to form a coating film, a substance imparting surface tension having a surface tension value equal to or less than that of the coating solution before spreading is added to the coating solution being in contact with the support during or after the spreading of the coating solution. In this case, the substance to be added does not contains a component not contained in the coating solution before spreading and the boiling point thereof is below that of at least one component in the components of the coating solution. After the added substance is added to the coating film during or after spreading, the coating film is heated to the boiling point of the added substance or higher.