Abstract: Provided is a guide device for puncturing with a puncture needle from a puncture point A provided at a vicinity of a first point B on a waist of a patient to a target point D inside a patient's body, the target point D corresponding to a second point C different from the first point B on the waist. The guide device includes a guide part for guiding the puncturing with the puncture needle, and a support base for supporting the guide part and abutting on the waist. A portion of the support base is configured to define a first angle with respect to a straight line connecting the puncture point A and the second point C, and the guide part is provided at a second angle with respect to a line perpendicular to the support base. The first angle is defined by the puncture point A, the second point C and the first point B, and the second angle is defined by the puncture point A, the target point D and the second point C.