This invention provides a phantom whose light propagation characteristics and acoustic propagation characteristics are similar to those of human tissues and which allows detection of an absorber also with an ultrasonic wave diagnostic apparatus and allows adjustment of the oxygen saturation.A phantom has light absorbers 12a to 12d in a phantom base material 11, in which the light absorbers 12a to 12d approximate the light absorption coefficient ratio at two or more wavelengths to that of biological tissues, and the acoustic propagation characteristics of the phantom base material 11 and the light absorbers 12a to 12d are different from each other.