A lubrication monitoring apparatus for a machine, in which an oil pressure gauge detects the pressure of lubricating oil of the filter, a first oil thermometer detects the temperature of lubricating oil before lubricating the mechanical section, a second oil thermometer detects the temperature of lubricating oil in the vicinity of the outlet of the lubricated mechanical section, and a warning device gives warning when any of the oil pressure, oil temperature, and oil temperature difference is out of a predetermined range.