A stress evaluation apparatus, a stress evaluation method, and a program for evaluating stress received by an operator during when an in-vehicle device is operated by an upper limb are provided. The apparatus includes a detection sensor, a calculation process portion and an evaluation portion. The detection sensor detects a muscle potential of a measuring object muscle of the operator. The calculation process portion receives time series information of the muscle potential to calculate strength information. The evaluation portion compares the strength information with an evaluation standard to make an evaluation of stress of the operator. The method includes detecting a muscle potential of a measuring object muscle, receiving time series information of the muscle potential to calculate strength information, and comparing the strength information with an evaluation standard to evaluate stress. A medium storing a computer-executable program that causes a computer to perform the above-described method is provided.
