A resin composition for printed circuit board contains a thermosetting resin and an inorganic filler containing magnesium oxide. A volume average particle size of the magnesium oxide is from 2 μm to 10 μm, inclusive. In a distribution of a particle size of the magnesium oxide, the particle size has maximal frequencies in a first range of from 0.3 μm to 1 μm, inclusive, and in a second range of from 2 μm to 10 μm, inclusive, a maximal volume frequency in the first range is 5% or less, and a maximal volume frequency in the second range is 12% or more. A ratio of 50% accumulated particle size D50 with respect to specific surface area diameter of the magnesium oxide is 4 or less, and a ratio of 90% accumulated particle size D90 with respect to 10% accumulated particle size D10 of the magnesium oxide is 10 or less.