PURPOSE: To obtain the subject compsn. which has a low viscosity and a high cure-sensitivity and gives a shaped article with a low cure shrinkage.

CONSTITUTION: The resin compsn. contains 10-70wt.% (based on the compsn.) ethylenically unsatd. monomer component comprising a compd. of the formula: CH2=CHCO(OR)n0OR' (wherein R is a1-4C alkylene; R' is a 6-15C alkyl group having an alicyclic structure; and (n) is an integer of 0-10) and/or a compd. of the formula: CH2=CHCO(OR)OR'O(RO)mCOCH=CH2 (wherein R is a 1-4C alkylene; R' is a 6-15C alkylene group having an alicyclic structure; and/(n) and (m) are each an integer of 0-10), an ethylenically unsatd. oligomer. and a photopolymn. initiator.