Patent ID: 8333637

Claim:
A manufacturing method of a transfer casting metal mold to cast an optical surface of a reflection mirror used in a projection optical system by transfer casting, comprising: forming a transfer optical surface by cutting or grinding a metal material in a first process; and performing a smoothing process in a second process by radiating an energy beam onto the transfer optical surface after the first process, wherein a power spectrum density function (hereinafter called a PSD function =A/f B ) describing a surface status of the transfer optical surface processed by the first process satisfies that: 1×10 −8 ≦A ≦1×10 −6 (1) 1/1000 <f <1 (2) 1<B<3 (3) wherein, A denotes a constant (μm 3−B ), f denotes a space frequency (μm −1 ) of surface roughness and B denotes an exponent of the space frequency.