A resin composition comprising: a ferrite; and a thermosetting resin, wherein the content of the component is 70% or more by mass and 98% or less by mass, on the basis of 100% by mass as nonvolatile components in the resin composition, and the content of the component is 1% or more by mass and 30% or less by mass, on the basis of 100% by mass as nonvolatile components in the resin composition, and wherein the resin is characterized in that: a carbon amount included in the component is 0.1% or less by mass relative to 100% by mass of the component, wherein the carbon amount included in the component is measured using a carbon analyzer; in the carbon analyzer, a ferrite to be measured is burnt by a high frequency induction furnace, and then, the carbon amount therein can be obtained by measuring amounts of carbon monoxide and carbon dioxide thus produced by an infrared light absorption method; in the carbon analyzer, an oxygen gas pressure is made to 2.5 kg/cm 2, and a nitrogen gas pressure is made to 2.8 kg/cm 2; first, the carbon amount in a standard sample whose carbon amount is known and almost in the same level as that of the ferrite to be measured is measured; next, a blank test is carried out without using the ferrite; then, a conversion coefficient is calculated; next, the ferrite to be measured is measured by using the carbon analyzer, and the carbon amount therein is calculated; when the component is surface-modified with a surface treating agent, the ferrite to be measured is heated at 500°C for 6 hours in an electric furnace with flowing nitrogen at the flow rate of 100 mL/minute to remove the surface treating agent on the ferrite surface prior to measurement of the carbon amount, a relative permeability (10 MHz) of a cured product obtainable by thermally curing the resin composition at 180°C for 90 minutes is 8 or more, and a maximum point strength (23°C) of a cured product obtainable by thermally curing the resin composition at 190°C for 90 minutes is 40 MPa or more. a ferrite; and a thermosetting resin, wherein the content of the component is 70% or more by mass and 98% or less by mass, on the basis of 100% by mass as nonvolatile components in the resin composition, and the content of the component is 1% or more by mass and 30% or less by mass, on the basis of 100% by mass as nonvolatile components in the resin composition, and wherein the resin is wherein the content of the component is 70% or more by mass and 98% or less by mass, on the basis of 100% by mass as nonvolatile components in the resin composition, and the content of the component is 1% or more by mass and 30% or less by mass, on the basis of 100% by mass as nonvolatile components in the resin composition, and wherein the resin is a carbon amount included in the component is 0.1% or less by mass relative to 100% by mass of the component, wherein the carbon amount included in the component is measured using a carbon analyzer; in the carbon analyzer, a ferrite to be measured is burnt by a high frequency induction furnace, and then, the carbon amount therein can be obtained by measuring amounts of carbon monoxide and carbon dioxide thus produced by an infrared light absorption method; in the carbon analyzer, an oxygen gas pressure is made to 2.5 kg/cm 2, and a nitrogen gas pressure is made to 2.8 kg/cm 2; first, the carbon amount in a standard sample whose carbon amount is known and almost in the same level as that of the ferrite to be measured is measured; next, a blank test is carried out without using the ferrite; then, a conversion coefficient is calculated; next, the ferrite to be measured is measured by using the carbon analyzer, and the carbon amount therein is calculated; when the component is surface-modified with a surface treating agent, the ferrite to be measured is heated at 500°C for 6 hours in an electric furnace with flowing nitrogen at the flow rate of 100 mL/minute to remove the surface treating agent on the ferrite surface prior to measurement of the carbon amount, a relative permeability (10 MHz) of a cured product obtainable by thermally curing the resin composition at 180°C for 90 minutes is 8 or more, and a maximum point strength (23°C) of a cured product obtainable by thermally curing the resin composition at 190°C for 90 minutes is 40 MPa or more.