NOVELTY - A glycoluril compound (I), is new.    USE - Glycoluril compound is used in epoxy resin composition, polyester resin composition, thermosetting resin composition, alkali developing-type photocurable heat-curable resin composition, olefin resin composition, curable composition, electron beam-curable resin composition and silicone resin composition for forming hardened materials for sealing optical semiconductor elements (all claimed), transistors, diodes, thyristors, capacitors, resistors and coils for LEDs, light receiving elements, displays, and solar cells. Can also be used for structural material, adhesive agent and coating material for decoration articles, building materials, motor vehicle components, aerospace materials, leisure sports instruments.    ADVANTAGE - The resin composition containing glycoluril compound provides lightweight hardened materials with excellent dielectric characteristics, heat resistance, adhesiveness, moisture resistance, mechanical properties, adhesive ness, solvent resistance, acid resistance, flexibility, thermal shock resistance and workability and reduced size.    DETAILED DESCRIPTION - A glycoluril compound of formula (I), is new.    Z=carboxyalkyl, glycidyl or allyl;    R1,R2=H, lower alkyl or phenyl;and    R3-R5=H or Z.    (i) When Z is carboxyalkyl, R3-R5 is carboxyalkyl; and (ii) when Z is allyl, R5 is H. INDEPENDENT CLAIMS are included for the following:    (1) epoxy resin composition, which comprises hardening agent, a crosslinking agent containing 1,3,4,6-tetrakis(carboxyalkyl)glycoluril compound, and amine;    (2) polyester resin composition, which comprises polyester resin (a) obtained by carrying out polycondensation reaction of 1,3,4,6- tetrakis(carboxyalkyl)glycoluril compound, glycol, and ( beta )-hydroxyalkylamide-type hardening agent (b);    (3) thermosetting resin composition, which comprises glycidyl glycoluril compound and phenol resin;    (4) alkali developing-type photocurable heat-curable resin composition, which comprises glycidyl glycoluril compound, photosensitive prepolymer having 2 or more unsaturated double bond in 1 molecule, and a photoinitiator;    (5) olefin resin composition, which comprises allyl glycoluril compound, and an olefin polymer;    (6) curable composition, which comprises tetraallyl glycoluril compound as organic compound having alkenyl group (A), compound (B) having at least 3 or more hydrosilyl groups in 1 molecule, and hydrosilylation catalyst (C);    (7) electron beam curable resin composition, which comprises polyolefin resin, and crosslinking agent; and    (8) silicone resin composition, which comprises polysiloxane having at least 2 alkenyl groups bonded with silicon atom, polysiloxane crosslinking agent having at least two hydrogen atoms bonded with silicon atom, hydrosilylation reaction catalyst, and 0.1-10 parts mass allyl glycoluril compound with respect to total 100 parts mass polysiloxane, crosslinking agent and catalyst.