To provide a light reflection sheet and a light source unit, capable of reducing front luminance unevenness and oblique luminance unevenness.

A light reflection sheet 1 comprises a sheet base material 11, at least one surface of which has an optical transparency control portion 12 to control optical transparency of the base material 11. In an opaque component ratio distribution chart, in which the lateral axis represents a relative position in a plane in a predetermined direction and the vertical axis represents an opaque component ratio in the relative position in the plane, a plurality of peak values of the opaque component ratio and a plurality of bottom values of the opaque component ratio exist, and an arithmetic average value of the opaque component ratios between neighboring peak value and bottom value is larger than an arithmetic average value of the opaque component ratios at all the points distributed between the neighboring peak value and bottom value.