A guide instrument for passing a medical needle with thread through or between body tissues has first and second shafts mounted to be pivotally movable to each other and is formed with, on the first shaft, a needle stand for making the needle with thread stand up and holding the needle with thread, a hole for guiding the thread, and a slit and with, on the second shaft, a needle receiver for receiving the needle when the shafts are made close while the needle with thread stands up at the needle stand. When the shafts 1, 2 are made close while the needle with thread stands up at the needle stand, the needle with thread passes through and between the body tissues and is engaged with the needle receiver. When the shafts are made open, the needle with thread while keeping the engagement with the needle receiver separates from the needle stand, and therefore, the needle with thread can be guided from the first shaft to the second shaft. Where a container for containing the needle with thread is formed in continuation with the needle stand on the parting faces of the first and second shafts, the container can prevent the needle with thread from dropping out, as well as can prevent the body tissues from being damaged by the needle, before the needle reaches an affected area at a time of ligation or suture.