A device for one-handed insertion of a guidewire into a vessel or cavity is provided. The device has a body, an actuator carriage, a guidewire feed, and a syringe. The body has a handle, a guideway, and a clip to retain the syringe. The syringe has a barrel and a plunger with a flange and a guidewire passage. The actuator carriage has a trigger and a clip to grasp the syringe plunger flange. The actuator carriage slides along the body guideway. The guidewire feed has a wire feed surface. The thumb engages wire at the wire feed surface to advance and retract the wire through the guidewire passage and a finger moves the trigger to move the syringe plunger rearwardly and/or forwardly, while the remaining fingers of the one hand grasp the handle. The device allows the user to sense resistance encountered by the tip of the wire.