The present invention provides a fluorine-containing volume holographic data recording material making it unnecessary to provide a step of eliminating a specific solvent even in the case of a thick film, and having high hologram performance and good dynamic range. There is provided a composition comprising a base polymer (a), a liquid monomer (b) and a photo-initiator (c), wherein the base polymer (a) is an amorphous polymer comprising a fluorine-containing monomer as a structural unit and having a fluorine content of 26 to 80% by mass, the liquid monomer (b) comprises at least one liquid monomer (b1) initiating polymerization by means of activated species generated from the photo-initiator (c), the photo-initiator (c) is a compound causing the liquid monomer (b1) to initiate polymerization by exposure to light having excellent coherence and, and a refractive index of the liquid monomer (b) is higher than an average refractive index of a mixture of the base polymer (a) and the photo-initiator (c).