PURPOSE: To ensure an iridescent color effect, and to improve design properties by forming a first layer composed of reduced titanium mica and a tatanium mica dispersing layer, etc., and a second layer consisting of a thermoplastic resin having specific all-ray transmittance to the thermoplastic resin having specific all-ray trasmittance.

CONSTITUTION: In a designable composite sheet 1, a black titanium oxide coated layer obtained by reducing one part of titanium dioxide is formed to a thermoplastic resin having all-ray transmittance of 60% when the resin is 1mm thick and a first layer 2, in which reduced titanium mica made up of scaly mica particles having the titanium dioxide coated layer and titanium mica composed of similar scaly mica particles are dispersed, onto the titanium oxide coated layer. A second layer 3 consisting of a white, black or colored thermoplastic resin having all-ray trasmittance of 50% or less is formed. The relationship of the thickness of the first layer 2 and the dispersion ratio of reduced titanium mica and titanium mica dispersed in the first layer is set so as to satisfy 0.01/A≤B≤0.5/A.