Abstract: Disclosed is a reflective sheet which contains a resin composition including not less than 50 volume % and less than 80 volume % of a polypropylene resin (A) and not less than 20 volume % and less than 50 volume % of a resin (B) which causes phase separation from the polypropylene resin at a temperature at which the polypropylene resin can be stretched, and has a pore inside. The reflective sheet is characterized in that, in a cross section of the reflective sheet in the thickness direction, the standard deviation of the ratio (X/Z) between the length (X) in the plane direction and the length (Z) in the thickness direction of the resin (B) phase is not less than 0.2.

Abstract: A method of producing a polyolefin porous film, including: a step of melt-kneading a resin which contains a polyolefin with a viscosity-average molecular weight of 300,000 or more as a main ingredient, together with a non-reactive gas using an extruder(s) (melt-kneading step); a step of forming the melt-kneaded resin into a non-porous solid resin form having an arbitrary shape (forming step); and a step of making the non-porous solid resin form porous (making-porous step).