Disclosed is a liquid preparation for forming an epoxy resin, which enables to obtain a cured product having both high transparency and high bending strength, while maintaining good handleability in a liquid state. Specifically disclosed is a liquid preparation for forming an epoxy resin, which contains an agent A and an agent B. The agent A contains a modified epoxy resin (I) obtained from at least one compound (i) having at least one functional group represented by the formula (1) below in a molecule and a compound (ii) having a glycidyl group in a molecule, and an inorganic particle (II), and the agent (B) contains a curing agent (III). formula (1) (In the formula, R1 and R2 each represents an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an aralkyl group, a heterocyclic group or a halogenated, aminated or nitrated derivative of any of them.) Also specifically disclosed is a liquid preparation for forming an epoxy resin, which contains an agent A' and an agent B'.The agent A' contains the modified epoxy resin (I), and the agent B' contains the inorganic particle (II) and the curing agent (III).