A reacting apparatus includes a reactor having a supply port and a discharge port, a first member connected to the surface of the reactor having a through hole associated with the supply port, and a second member connected to the surface of the reactor and having a through hole associated with the discharge port, a supply pipe connected to the supply port by way of the through hole of the first member, to supply a fluid before the reaction to the supply port, and a discharge pipe connected to the discharge port by way of the through hole of the second member, to discharge a fluid after the reaction from the discharge port. The supply port and discharge port include a portion covered by a surface of the first member and a portion communicating with the through hole of the first member. The discharge port includes a portion covered by a surface of the second member and a portion communicating with the through hole of the second member. A first opening of the through hole of the first member includes a portion covered by the surface of the reactor and a portion communicating with the supply port. A second opening of the through hole of the second member includes a portion covered by the surface of the reactor and a portion communicating with the discharge port.