It is an object of the present invention to obtain an optically transparent nano-dispersed polymer blend extrudate and a transparent resin having a microscopic dispersion structure in which incompatible polymer blend is melted and kneaded, one of resins is formed into a matrix, a size of dispersed phase of the other resin is controlled to 300 nm or less, more preferably 100 nm or less. Extra additive such as a compatibilizer is not added. When the incompatible polymer blend is melted and kneaded using a high shearing and forming apparatus having an inner feedback type screw under a condition that the screw rotation speed is 600 rpm to 3000 rpm, the rotation speed of the inner feedback type screw is increased, the kneading time is set under constant rotation speed, the high shearing forming condition is adjusted, and a structure in which a size of dispersed phase is controlled to 300 nm or less, more preferably 100 nm or less is formed.