The invention relates to a weighing device for a continuous dry mortar production line. The weighing device comprises a powder metering mechanism and a mortar metering mechanism which are respectively arranged on the continuous dry mortar production line, wherein the powder metering mechanism comprises a support frame, a pull rod, a metering hopper, a conveying screw and a feeding screw; the metering hopper is suspended on the support frame through at least two pull rods, and the conveying screw and the feeding screw are respectively communicated with an output port and an input port of the metering hopper; the mortar metering mechanism comprises a metering panel and a feed plate arranged on the upper end of the metering panel, a plurality of small metering bins which are evenly distributed are arranged on the metering panel, a feed inlet is formed in the feed plate, the position of the feed inlet corresponds to the small metering bins, and the feed inlet is distributed along the motion trace direction of the metering panel. The weighing device has the beneficial effects of being applicable to dry mortar continuous production and accurate in metering.