According to the present invention, there is provided a low dielectric loss tangent resin composition containing a crosslinking component having a weight average molecular weight of not more than 1,000 and a plurality of styrene groups and represented by the formula null1null, 1 wherein R is a hydrocarbon skeleton which may have a substituent, R1 is hydrogen, methyl or ethyl, m is an integer of 1-4 and n is an integer of 2 or more, and further containing at least one member selected from a high polymer having a weight average molecular weight of not less than 5,000 and a filler, which resin composition can give a cured product having a good flexibility, high tensile strength and low dielectric constant and dielectric loss tangent.