A CAI system for vehicle repair workers is disclosed. The CAI system for supporting an instruction for one group consisting of a plurality of training participants includes a storage device for storing attribute data of each participant, a keyboard for inputting degree-of-master basic data of each participant for every plurality of instruction items, and a control unit for processing the data, the control unit evaluates a degree of master of each participant for every instruction item, calculates an overall evaluation of the concerned instruction item of the target group, selects the instruction item exhibiting a low degree of master by comparing the overall evaluations of the concerned instruction item, and selects which instruction target person should be instructed with respect to the selected instruction item. The CAI system is capable of efficiently enhancing a working efficiency of one working group consisting of the plurality of workers.