PURPOSE: A float sensor is provided to prevent a sensor from malfunctioning by preventing a float guide section from being bent due to medicine liquid contained in a storage tank. CONSTITUTION: A float sensor includes a float guide section(10) and a float(20). The float guide section(10) is vertically installed in a storage tank having medicine liquid therein. The float(20) is positioned around the float guide section(10) in such a manner that the float(20) is moved according to variation of a water level. A pair of electrodes(5a) are installed in an internal space of the float guide section(10) in order to receive voltage. A permanent magnet is accommodated in the float(10). The float guide section(10) has a hollow pipe structure. A plurality of guide lines are formed at an outer peripheral surface of the float guide section(10).
