A silica-containing resin composition, characterized by comprising a resin and silica particles in an amount of 5 to 300 parts by mass, with respect to 100 parts by mass of the resin, wherein the silica particles are produced through hydrolysis of a silicon alkoxide and satisfy the following requirements (a) to (c): (a) the silica particles have a specific surface area, as determined through a nitrogen absorption method, of 20 to 500 m 2 /g; (b) the silica particles have a percent moisture absorption of 5.0 mass% or less at 23°C and at a relative humidity of 50%; and (c) the silica particles contain substantially no metallic impurity or halogen, and the amount of sodium is less than 1 ppm, the amount of iron is less than 1 ppm and the amount of chloride is less than 2 ppm; and the production of the silica particles includes steps and, wherein: step is a step of using at least one member selected from among ammonia, primary to tertiary amines, and a quaternary ammonium, as a hydrolysis catalyst, and step is a step of hydrolyzing a silicon alkoxide in water and/or a hydrophilic organic solvent serving as a reaction medium in the presence of the hydrolysis catalyst, with the temperature of the reaction medium being adjusted to 60°C or higher and the ratio by mole of water to silicon (H 2 0/Si) is maintained at 25 or higher, such that the silica particles produced have a moisture absorption amount per surface area thereof of 0.5 mg/m 2 or less at 23°C and a relative humidity of 50%, a specific surface area, as determined through a nitrogen absorption method, of 20 to 500 m 2 /g and a ratio (D2/D1) of mean particle size measured through dynamic light scattering to mean particle size measured through the BET method of 1.6 or lower. (a) the silica particles have a specific surface area, as determined through a nitrogen absorption method, of 20 to 500 m 2 /g; (b) the silica particles have a percent moisture absorption of 5.0 mass% or less at 23°C and at a relative humidity of 50%; and (c) the silica particles contain substantially no metallic impurity or halogen, and the amount of sodium is less than 1 ppm, the amount of iron is less than 1 ppm and the amount of chloride is less than 2 ppm; and the production of the silica particles includes steps and, wherein: step is a step of using at least one member selected from among ammonia, primary to tertiary amines, and a quaternary ammonium, as a hydrolysis catalyst, and step is a step of hydrolyzing a silicon alkoxide in water and/or a hydrophilic organic solvent serving as a reaction medium in the presence of the hydrolysis catalyst, with the temperature of the reaction medium being adjusted to 60°C or higher and the ratio by mole of water to silicon (H 2 0/Si) is maintained at 25 or higher, such that the silica particles produced have a moisture absorption amount per surface area thereof of 0.5 mg/m 2 or less at 23°C and a relative humidity of 50%, a specific surface area, as determined through a nitrogen absorption method, of 20 to 500 m 2 /g and a ratio (D2/D1) of mean particle size measured through dynamic light scattering to mean particle size measured through the BET method of 1.6 or lower. step is a step of using at least one member selected from among ammonia, primary to tertiary amines, and a quaternary ammonium, as a hydrolysis catalyst, and step is a step of hydrolyzing a silicon alkoxide in water and/or a hydrophilic organic solvent serving as a reaction medium in the presence of the hydrolysis catalyst, with the temperature of the reaction medium being adjusted to 60°C or higher and the ratio by mole of water to silicon (H 2 0/Si) is maintained at 25 or higher, such that the silica particles produced have a moisture absorption amount per surface area thereof of 0.5 mg/m 2 or less at 23°C and a relative humidity of 50%, a specific surface area, as determined through a nitrogen absorption method, of 20 to 500 m 2 /g and a ratio (D2/D1) of mean particle size measured through dynamic light scattering to mean particle size measured through the BET method of 1.6 or lower.