A protrusion/recess structure in which fine particles will not drop easily and which will not be deformed easily is provided, and a producing method for the same is provided. In the protrusion/recess structure (porous film), protrusions or recesses (fine corrugations) are formed in a surface. The protrusion/recess structure is formed from plural fine particles and an amphipathic high molecular compound having a catechol group. The high molecular compound at least partially coats a surface of the fine particles, to adhere the fine particles to one another. A diameter of the recesses is larger than a diameter of the fine particles. Cast film is formed from solution containing the fine particles and the high molecular compound having the catechol group. Condensation on the cast film is performed, and organic solvent and water droplets created by the condensation are evaporated to produce the protrusion/recess structure.