A manufacturing method of a semiconductor element provided with a semiconductor layer containing a crystal of an organic semiconductor material of the invention includes the steps of (i) forming a frame (12) on a substrate (base) (11), and (ii) forming the semiconductor layer (crystal (13)) inside the frame (12). The step (ii) includes a crystal forming step in which a solution (21) containing the organic semiconductor material and a liquid medium is placed inside the frame (12) and then the crystal (13) is formed from the solution (21).