To obtain a molded product which shows no change in quality over time after its manufacture and exerts a stable hue without any uneven coloring or streak, in a process for manufacturing a thermoplastic resin molded product involving in-house coloring by molding manufacturers without any color matching process by coloring manufacturers.

In a process for manufacturing the thermoplastic resin molded product, a monocolored batch is prepared by melt kneading from 0.01 to 70 wt.% dyestuff and a thermoplastic resin (base resin). Subsequently, at least 0.5 pts.wt. monocolored batch is compounded with 100 pts.wt. thermoplastic resin (dilution resin) and molded while subjected to coloring.