A liquid level detection apparatus includes a rotation member axially supported by a fixed member. The rotation member includes the following. A contact portion press contacts an end surface making connection between both side surfaces of a magnet member. A pair of elastic deformation portions are protruded from the contact portion; each elastic deformation portion engages with a side surface of the magnet member in an elastically deformed state resulting from press to the magnet. A pair of pawl portions are protruded respectively from the elastic deformation portions while enabling the magnet member to be sandwiched between the contact portion and the pawl portions. A pair of plastic deformation portions are protruded from the elastic deformation portions, respectively; each of the plastic deformation portions engages with the side surface of the magnet member in a plastically deformed state resulting from the press to the magnet.