1. A mixed reality presentation apparatus which generates a three-dimensional virtual image associated with a collaborative operation to be done by a plurality of operators in a predetermined mixed reality environment, and displays the generated virtual image on see-through display devices respectively attached to the plurality of operators, comprising: first sensor means for detecting a position of each of actuators which are operated by the plurality of operators and move as the collaborative operation progresses; second sensor means for detecting a view point position of each of the plurality of operators in an environment of the collaborative operation; and generation means for generating three-dimensional images for the see-through display devices of the individual operators, said generation means generating a three-dimensional virtual image representing an operation result of the collaborative operation that has progressed according to a change in position of each of the plurality of actuators detected by said first sensor means when viewed from the view point position of each operator detected by said second sensor means, and outputting the generated three-dimensional virtual image to each see-through display device.