To provide an oil-degradation determination apparatus for detecting the degradation of oil circulated in and supplied to an engine (10), on the basis of measured data on an electric pump (41) that circulates and supplies oil, without using a special sensor to detect the degradation of oil.
An oil-degradation determination apparatus includes: electric-current initial-value storing means (1a) which measures an electric-current value of a driving current used to operate an electric pump (41) at a predetermined constant revolution when the engine (10) is driven immediately after an oil change, and stores the electric-current value as an electric-current initial value; pump-driving-time electric-current value measurement means (2a) which collects data by measuring the electric-current value of the driving current used to operate the electric pump (41) at the predetermined constant revolution when the engine (10) is driven a predetermined time after the oil change; comparison means (3) which compares the electric-current initial value with the electric-current value thus measured; and determination means (4) (4) which determines that the viscosity of the oil has become low when the difference between the two electric-current values thus compared by the comparison means (3) is equal to or more than a predetermined value.