A fibrillated liquid crystal polymer powder containing fibrillated liquid crystal polymer particles. A paste containing a dispersion medium and the fibrillated liquid crystal polymer powder. A method of producing the fibrillated liquid crystal polymer powder. A resin multilayer substrate obtained by laminating a plurality of resin sheets including at least one layer of a liquid crystal polymer sheet. On a surface of at least one layer of the liquid crystal polymer sheet, a thickness adjustment layer made of a fibrillated liquid crystal polymer powder containing fibrillated liquid crystal polymer particles is provided in a region insufficient in thickness when at least the plurality of resin sheets are laminated.