To obtain the subject product suitable for forming a black resist pattern, providing a photopolymerizable composition for forming the pattern, excellent in developing characteristics due to dispersibility in preparation of the composition, by coating carbon black with a polyfunctional epoxy resin and adjusting the gel fraction of the resin.

This carbon black is coated with a polyfunctional epoxy resin (e.g. glycidylamine type epoxy resin) and has 20-70% adjusted gel fraction of the polyfunctional epoxy resin of the coated layer. The ratio of the resin to the total of the carbon black and resin is generally selected from a range of 5-40 wt.%. The get fraction adjustment is carried out by using carbon black having ≥15 mg/g total oxygen amount and the ratio of the total oxygen amount/the specific surface area of ≥0.1 mg/m2, controlling a drying treatment temperature at 40-130°C and regulating dehydrating conditions before the drying treatment and the arrangement of resin coated carbon black in a drying process, etc.