It is an object of the present invention to provide a composition for light emitting diodes with which it is possible to obtain an organic EL element that includes an organic layer formed using a high molecular weight material and whose service life can be extended as compared with that of conventional organic EL elements. The present invention provides a composition for light emitting diodes containing a high molecular weight compound and a thermally crosslinkable low molecular weight compound, wherein the thermally crosslinkable low molecular weight compound includes a compound that has two or more thermally crosslinkable structures in a molecule. The thermally crosslinkable low molecular weight compound preferably includes a compound that contains two or more thermally crosslinkable structures selected from the group consisting of an acrylate structure, a methacrylate structure, and a maleimide structure in a molecule.