A treatment liquid application apparatus comprising: a front-side application supply pan configured to store a treatment liquid to be applied to a front side of a to-be-recorded-on medium; a back-side application supply pan configured to store the treatment liquid to be applied to a back side of the to-be-recorded-on medium; a treatment liquid cartridge configured to store the treatment liquid; a supply line (h) configured to supply the treatment liquid stored in the treatment liquid cartridge to the front-side application supply pan and the back-side application supply pan, respectively; a reserve tank that has higher airtightness than the front-side application supply pan and the back-side application supply pan; a filter chamber that includes a filter for removing foreign matter contained in the treatment liquid through a circulation during an application of the treatment liquid to the to-be-recorded-on medium; a front-side application removing and circulating line (c) configured to connect the front-side application supply pan with the reserve tank and the filter chamber; a back-side application removing and circulating line (d) configured to connect the back-side application supply pan with the reserve tank and the filter chamber; a returning line (e) that is connected from the filter chamber to the supply line in-line and is configured to return the treatment liquid from which the foreign matter has been removed by the filter to the front-side application supply pan and the back-side application supply pan; a liquid flow creation part configured to create flows of the treatment liquid in the supply line, the front-side application removing and circulating line, the back-side application removing and circulating line and the returning line; and a plurality of valves installed on the supply line, the front-side application removing and circulating line, the back-side application removing and circulating line and the returning line for switching thereamong a line through which the treatment liquid flows; and a control part configured to control the liquid flow creation part and the valves to supply the treatment liquid to at least either of the front-side application removing and circulating line and the back-side application removing and circulating line in a process of supplying the treatment liquid to the front-side application supply pan and the back-side application supply pan at a time of power supply being turned on in the treatment liquid application apparatus. a front-side application supply pan configured to store a treatment liquid to be applied to a front side of a to-be-recorded-on medium; a back-side application supply pan configured to store the treatment liquid to be applied to a back side of the to-be-recorded-on medium; a treatment liquid cartridge configured to store the treatment liquid; a supply line (h) configured to supply the treatment liquid stored in the treatment liquid cartridge to the front-side application supply pan and the back-side application supply pan, respectively; a reserve tank that has higher airtightness than the front-side application supply pan and the back-side application supply pan; a filter chamber that includes a filter for removing foreign matter contained in the treatment liquid through a circulation during an application of the treatment liquid to the to-be-recorded-on medium; a front-side application removing and circulating line (c) configured to connect the front-side application supply pan with the reserve tank and the filter chamber; a back-side application removing and circulating line (d) configured to connect the back-side application supply pan with the reserve tank and the filter chamber; a returning line (e) that is connected from the filter chamber to the supply line in-line and is configured to return the treatment liquid from which the foreign matter has been removed by the filter to the front-side application supply pan and the back-side application supply pan; a liquid flow creation part configured to create flows of the treatment liquid in the supply line, the front-side application removing and circulating line, the back-side application removing and circulating line and the returning line; and a plurality of valves installed on the supply line, the front-side application removing and circulating line, the back-side application removing and circulating line and the returning line for switching thereamong a line through which the treatment liquid flows; and a control part configured to control the liquid flow creation part and the valves to supply the treatment liquid to at least either of the front-side application removing and circulating line and the back-side application removing and circulating line in a process of supplying the treatment liquid to the front-side application supply pan and the back-side application supply pan at a time of power supply being turned on in the treatment liquid application apparatus.