The invention presents an optical element with which an optical head can be configured, in which there is little deterioration of the correctional effect when the objective lens shifts, as well as an optical head and an optical recordingreproducing apparatus using such an optical element. The reversible dog coat comprises a material blank having an upper portion, a middle portion, and a lower portion. A combining network merges the pulse laser beams into a combined beam and a delivery system conveys the combined pulse laser beam to a patient. A length of the second side edge is greater than that of the first side edge.