Provided are: a photostabilizer masterbatch in which the problems of the occurrence of blocking over time due to the effect of temperature fluctuations in the environment and the difficulty in handling due to the resulting solidification in aggregates are overcome; and a method of producing the same.The photostabilizer masterbatch is obtained by adding and mixing 80 to 300 parts by mass of (B) a hindered amine compound represented by the following Formula (1) with respect to 100 parts by mass of (A) a silica produced by a wet process and subsequently further adding and mixing 5 to 50 parts by mass of (C) a silica produced by a dry process: (wherein, R1 represents a hydrogen atom, a hydroxy group, an alkyl, hydroxyalkyl, alkoxy or hydroxyalkoxy group having 1 to 30 carbon atoms, or an oxy radical; and R2 represents an alkyl group having 1 to 30 carbon atoms, an alkenyl group having 2 to 30 carbon atoms, or a group represented by the following Formula (2)) (wherein, R3 represents the same as R1 in the Formula (1)).