The present invention relates to an automatic injection syringe for plants, and in one aspect, the present invention provides an automatic injection syringe for plants, including: a main body which stores therein an injection solution; a needle which is inserted into a plant body and configured to allow the injection solution in the main body to flow out to the outside; an injection unit which is disposed in the main body and defines a storage space for storing the injection solution; an elastic member which is configured to move the injection unit inside the main body toward the needle when the elastic member is released from a compressed state; and a releasing unit which releases the elastic member from the compressed state.