Double-needle liquid adding device

The double-needle liquid adding device comprises a first reagent needle, a second reagent needle and a control mechanism, the control mechanism comprises a guide fixing block, a first toothed bar, a second toothed bar and a rotating rod, the first toothed bar, the second toothed bar and the rotating rod penetrate through the guide fixing block, and the mounting direction of the rotating rod on the guide fixing block is perpendicular to the first toothed bar and the second toothed bar. A bearing is mounted at the end parts of the rotating rod and the guide fixing block, a gear mounting tube is sleeved on the rotating rod positioned in the guide fixing block, a gear is sleeved on the gear mounting tube, the lower end of the first toothed bar is connected with the upper end of the first reagent needle through a reagent needle fixing block, and the lower end of the second toothed bar is connected with the upper end of the second reagent needle through a reagent needle fixing block. By improving the specific struc