To provide a base film that can exhibit excellent electromagnetic conversion characteristics by keeping cupping within a predetermined range even if using a magnetic layer of hexagonal ferrite powder.

This biaxially oriented laminated film used for a base film of a coated magnetic recording tape using hexagonal ferrite powder for the magnetic layer includes an A-layer located in an outermost layer on the formed side of the magnetic layer, and a B-layer located in an outermost layer on the non-formed side of the magnetic layer where a difference (TMAb-TMAa) between the width direction expansion ratio (TMAa) of the A-layer and the width direction expansion ratio (TMAb) of the B-layer when applying a load of 1.0 MPa per unit cross-sectional area and causing a temperature rise from 30°C to 110°C is 0.05% or larger and smaller than 1.5%.