The present invention is a puncture apparatus with an automatic puncture function, that includes: an automatic puncture unit and an unintentional operation preventive member, wherein the automatic puncture unit comprises: a hollow needle tube a flexible sheath having the needle tube inserted therethrough a main body having one of the ends of the sheath fixed thereto a slider attached to the main body, the slider being capable of sliding in an axial direction relative to the main body a needle tube-maneuvering section, attached to the slider, capable of sliding in an axial direction relative to the slider, the needle tube-maneuvering section having an end section of the needle tube fixed thereto a retraction state-maintaining member for maintaining the needle tube-maneuvering section in the retracted state toward a proximal end an urging member, provided in the needle tube-maneuvering section, for urging a retracted state of the needle tube-maneuvering section toward the distal end an operation section for resetting the operation of the retraction state-maintaining member releasing the ejection force and projecting the needle tube-maneuvering section toward the distal end the needle tube-maneuvering section is provided to the slider for holding the operation section in an non-operating state and wherein the ejection force is released when the rear end of the slider is destroyed by applying a specific load or greater to the automatic puncture unit.
