Thermosetting resin composition, prepreg, laminate, metal foil-clad laminate, and circuit board

A thermosetting resin composition, containing 50 to 70 parts by volume of an inorganic filler with respect to 100 parts by volume of thermosetting resin solids and the inorganic filler,

• wherein the inorganic filler contains:
• (A) at least one type of particles selected from among gibbsite-type aluminum hydroxide particles, which have been subjected to a heat resistance process, and magnesium hydroxide particles having an average particle size (D50) of 1 to 15 μm;
• (B) aluminum oxide particles having an average particle size (D50) of 1.5 μm or less;
• (C) a molybdenum compound;
• (D) boehmite particles having an average particle size (D50) of 0.1 to 0.9 μm,
• wherein blending ratios (by volume) of the component (A), the component (B), the component (C) and the component (D) with respect to 100% as the total amount of inorganic filler are component (A):
• 30 to 70%, component (B):
• 1 to 30%, component (C):
• 1 to 10% and component (D):
• 10 to 30%, and
• the resistance process is performed such that a boehmite phase becomes less than 15% of the total, at a 1% dehydration temperature of 250° C. or higher.