In an apparatus for determining a state of attention of an operator by using an electroencephalogram, the state of attention of each operator is accurately determined without asking him or her to previously perform an explicit calibration task.The apparatus includes: a standby state detection section for detecting a time period during which an operator is making preparations prior to beginning a driving operation a determination criterion adjustment section for adjusting a determination criterion for determining a state of attention of the operator during a driving operation, the determination criterion adjustment section calculating an eye fixation related potential of the electroencephalogram signal of the operator measured at least in the time period by using the measured oculomotor signal of the operator, and adjusting the determination criterion based on the calculated eye fixation related potential a state-of-attention determination section for calculating an eye fixation related potential from the electroencephalogram signal and the oculomotor signal of the operator measured after beginning the driving operation, and determining a state of attention of the operator during the driving operation based on the calculated eye fixation related potential and the adjusted determination criterion and an output section for acting to call attention of the operator based on a result of determination.
