To provide a precision filter unit using a porous alumina membrane filter with excellent pressure resistance and an improved filtration flow rate.

The precision filter unit is provided at least with: the porous alumina membrane filter composed of an anode oxide film of aluminum and provided with micropores in which a regularization degree is 50% and the standard deviation of a pore diameter is within 10% of an average pore diameter; and a porous material to be brought into contact with the surface on one side at least of the porous alumina membrane filter, in which the average pore diameter is 500 nm to 10 mm, an opening area per unit area is wider than the opening area per unit area of the porous alumina membrane filter, and Young's modulus is larger than 660 MPa.