The utility model belongs to a feeding device for conveying powdery material, and relates particularly to an automatic compensation type electric feeder. The utility model includes a transmission mechanism, a shell body provided with a feed inlet and a discharge port, shell covers on both sides of the shell, a blade shaft in the shell supported by the shell covers, and blades on the blade shaft by a distributed connection. The utility model is characterized in that an active blade mechanism is installed in the contact end plane of each blade contacting the inner wall surface of the shell body, wherein the active blade mechanism consists of active blades and springs, grooves, which are corresponding to the shape and size of the active blades and can allow the active blades to freely go in or go out, are arranged in the outside end plane of the blades, spring holes are distributed in the groove bottom surface, springs are placed into the spring holes, the active blades are placed in the grooves, and the top end plane of the active blades hermetically contact the inner wall surface of the shell body after the bottom surface of the active blades contact the springs. The utility model has advantages of rational design, compact structure, good sealability, safety, reliability, energy saving and great convenience for use.