The present invention relates to a photoresist composition containing a photo radical generator, more specifically, to a photoresist composition which comprises (a) photoresist resin, (b) a photoacid generator, (c) an organic solvent and (d) a photo radical generator. The present photoresist composition reduces or prevents a sloping pattern formation due to a higher concentration of acid in the upper portion of the photoresist relative to the lower portion of the photoresist.