Disposable flow velocity measuring device having predetermined sensitivity to pressure change by using various types of ultra-thin films

A disposable flow velocity measuring device including: a first panel having a flow velocity measuring structure, and having additional micro protrusion patterns formed around the flow velocity measuring structure; a second panel separated from the first panel, and including a fluid channel through which a sample passes; a porous ultra-thin film formed on a portion, at which the first panel and the second panel come in contact with each other, so that the sample passing through the fluid channel does not directly come in contact with the flow velocity measuring structure, thereby separating the first panel and the second panel and removing micro-air bubbles included in the fluid passing through the fluid channel; a non-porous ultra-thin film formed in a partial region of the porous ultra-thin film; and a negative pressure forming unit for applying negative pressure in order to adsorb the first panel and the second panel.