A device for nucleic acid amplification reaction, comprising: a casing (100, 600) with an upper surface including a sample-dripping portion for receiving a liquid sample containing nucleic acid, the liquid sample being dripped from a nozzle; a reaction tube outwardly projecting from an end of the casing (100, 600); including a storage space therein; and being formed so as to be installed within a measurement apparatus; wherein the reaction tube holds at least a part of reagent required for the nucleic amplification reaction; a cleaning pot carrying cleaning fluid therein; a means allowing the cleaning fluid within the cleaning liquid pot to flow toward the sample-dripping portion (101; a filter configured to carry thereon the nucleic acid contained in the liquid sample; a filter-supporting body stored within the casing (100, 600) to support the filter in a manner such that the filter is capable of taking: a contacting position wherein the filter contacts with the liquid sample right below the sample-dripping portion; and a reaction position wherein the filter is positioned within the storage space of the reaction tube; and absorbing material capable of taking: a press-attaching position wherein the absorbing material is press-attached to the filter in the contacting position so that the filter absorbs the liquid sample contacting therewith; and a separating position wherein the absorbing material is removed from the press-attaching position so that the filter is allowed to freely move. a casing (100, 600) with an upper surface including a sample-dripping portion for receiving a liquid sample containing nucleic acid, the liquid sample being dripped from a nozzle; a reaction tube outwardly projecting from an end of the casing (100, 600); including a storage space therein; and being formed so as to be installed within a measurement apparatus; wherein the reaction tube holds at least a part of reagent required for the nucleic amplification reaction; a cleaning pot carrying cleaning fluid therein; a means allowing the cleaning fluid within the cleaning liquid pot to flow toward the sample-dripping portion (101; a filter configured to carry thereon the nucleic acid contained in the liquid sample; a filter-supporting body stored within the casing (100, 600) to support the filter in a manner such that the filter is capable of taking: a contacting position wherein the filter contacts with the liquid sample right below the sample-dripping portion; and a reaction position wherein the filter is positioned within the storage space of the reaction tube; and a contacting position wherein the filter contacts with the liquid sample right below the sample-dripping portion; and a reaction position wherein the filter is positioned within the storage space of the reaction tube; and absorbing material capable of taking: a press-attaching position wherein the absorbing material is press-attached to the filter in the contacting position so that the filter absorbs the liquid sample contacting therewith; and a separating position wherein the absorbing material is removed from the press-attaching position so that the filter is allowed to freely move. a press-attaching position wherein the absorbing material is press-attached to the filter in the contacting position so that the filter absorbs the liquid sample contacting therewith; and a separating position wherein the absorbing material is removed from the press-attaching position so that the filter is allowed to freely move.