Object To provide an illumination apparatus capable of suppressing a chromaticity fluctuation due to a view angle and an incident angle. The invention enables different threads to be checkpointed at different times in such a way that the checkpoints restore a consistent state of the threads at a new or recovering replica, even though the threads operate concurrently and asynchronously. A period for reading out the image signal input to the RAM one time is shorter than a period for writing in the image signal to the RAM. Based on the access contents, a join group request is issued for the group address used by the multicast delivery. In a preferred embodiment, linking the first and second points on the anal sphincter includes passing a first end of the anal sling, coupled to a first-side needle tool, through the anal sphincter at the first point and passing a second end of the anal sling, coupled to a second-side needle, through the anal sphincter at the second point.