[Problem] To provide an adhesive sheet which is used for a light-emitting diode device, and which is free from cracks and peeling off of the adhered portions. [Means for Solving the Problem] An adhesive sheet for a light-emitting diode device, which comprises a thermoplastic polymer containing epoxy groups and a compound containing functional groups which are addition reactive with the epoxy groups or a polymerization catalyst which can effect a ring opening polymerization of the epoxy groups, and in which said thermoplastic polymer is cross-linked so that its flowability is restrained.