To obtain a thermosetting resin composition which gives a cured item having very low water absorption properties without detriment to its high heat resistance and low permittivity by incorporating a thermosetting resin and a liquid crystal polyester into the same.

Examples of the thermosetting resin are an epoxy resin, a cyanate resin, a phenol resin, and a melamine resin, an epoxy resin being preferable in terms of reactivity and handleability. A liquid crystal polyester which forms an anisotropic melt at 400°C or lower is preferable, an example being one prepared from the combination of an aromatic dicarboxylic acid, an aromatic diol, and an aromatic hydroxycarboxylic acid. Preferably, a liquid crystal polyester in the form of a powder is mixed with other ingredients, and the average particle size of the powder is preferably 0.1-100 μm. The compounding ratio by wt. of the thermosetting resin to the liquid crystal polyester is 100/(5-50). The thermosetting resin may contain a curing agent and a cure catalyst as required.