A contact determination processing apparatus includes a contact sensor disposed in a steering wheel of and inside a vehicle. The contact sensor has an output that depends on a contact or non-contact state between the steering wheel and an occupant in the vehicle. The apparatus further includes a contact determination ECU that detects the contact state when the output of the contact sensor is greater than or equal to a predetermined threshold, and detects the non-contact state when the output is less than the predetermined threshold. In addition, the apparatus includes a temperature detection module that detects the ambient temperature of the steering wheel. The contact determination ECU includes a threshold changing section that changes the threshold based on a detection result of the temperature detection module.