To obtain a new fullerene derivative having ability to form thin film or the like, and useful for a photosensor, a photoelectrochemical element, an electrophotographic photoreceptor or the like.

A compound of formula I [x is 1 or 0; R is a group of formula II; (n) is 2-12; Y is a halogen], preferably a compound of formula III. The compound of formula I is obtained, for example, by the following process: at first, a compound of the formula: R and a compound of the formula: Br(CH2)Br (e.g. 1,4-dibromobutane) are made to react with each other to synthesize Br(CH2)n(R)x(CH2)nBr [e.g. a compound of formula IV (n=4)]; subsequently this product is made to react with one equivalent of sodium azide in a polar solvent to synthesize a compound of the formula: N3(CH2)n(R)x(CH2)nBr; further this compound is made to react with fullerene in a solvent such as chlorobenzene to synthesize a compound of formula V; and finally this compound is made to react with trimethylammonium in a solvent such as toluene under shading.