Oil level detecting switch, which detects an amount of lubricant oil stored in an oil pan, includes: a switch case having through-holes to permit entry and discharge of oil into and out of the switch case; a float of a spherical shape having smaller specific gravity than the oil and conductive outer surface and provided within the switch case for vertical movement in response to increase/decrease of the oil; and a plurality of fixed contacts provided on the bottom surface of the switch case such that the fixed contacts are placed in a conducting state by the float contacting the fixed contacts.