The invention relates to a cake shaped slow release fertilizer ejecting device. The device comprises a rack, a fertilizer delivery apparatus, a composting apparatus, a fertilizer ejecting pipeline and a single chip microcomputer. The rack is composed of an upper layer and a lower layer movably connected together; the fertilizer delivery apparatus comprises a stepping motor 1, a cam, a push rod fixed module, a push rod, a fertilizer barrel and a fertilizer delivery box; a fertilizer ejecting apparatus comprises a stepping motor 2, a gear rack and a gear; when fertilizer is not delivered, a fertilizer baffle plate is located at a fertilizer outlet at the lower end of the fertilizer barrel and blocks the fertilizer outlet, so that a cake shaped slow release fertilizer cannot fall; the push rod can drive the fertilizer delivery box to move forward while advancing, the fertilizer baffle plate then shifts forward to open the fertilizer outlet, the fertilizer delivery box moves to a position below the fertilizer outlet, and the cake shaped slow release fertilizer falls into the fertilizer delivery box. The cake shaped slow release fertilizer ejecting device provided by the invention can realize controllable single delivery and ejection of the cake shaped slow release fertilizer in order, and solves the difficulty of single fertilizer ejecting of cake shaped slow release fertilizers. The device can guarantee stable ejection of cake shaped slow release fertilizer, and solves the disadvantages of need for frequent movement, high cost and high labor intensity in artificial fertilization.