In a composition comprising (A) a reinforcing fiber containing a carbon fiber, (B) a resin particle, and (C) a matrix resin (C), the resin particle (B) comprises a spherical resin particle having an average particle diameter of 12 to 70 µm. In a composition comprising (A) a reinforcing fiber containing a carbon fiber, (B) a resin particle, and (C) a matrix resin, the resin particle (B) comprises (B1) a spherical small resin particle having a particle diameter less than an average fiber diameter of the reinforcing fiber (A) and (B2) a spherical large resin particle having a particle diameter not less than the average fiber diameter of the reinforcing fiber (A). The reinforcing fiber (A) may particularly comprise a carbon fiber. The resin particle (B) may particularly comprise a polyamide resin particle. The resin particle (B) may have an average particle diameter of 1 to 10 times as large as the average fiber diameter of the reinforcing fiber (A). In such a composition, the proportion of the resin particle (B) may be not more than 10% by weight (e.g., 1 to 5% by weight) in the total amount of the resin particle (B) and the matrix resin (C). A small amount of the resin particle achieves a sufficient reinforcing function of the reinforcing fiber.