Abstract: A combination of a semiconductor member and a metal member is selected appropriately from a view point of increasing an enhancement factor of a near-field light. A device (1) has a semiconductor member (101) and a metal member (102), a near-field light is generated at the metal member when an energy is supplied to the semiconductor member, the metal member is made of an alloy including a first metal and a second metal, a condition of Rm1<Rs<Rm2 is satisfied, wherein a resonance wavelength of the first metal is Rm1, a resonance wavelength of the second metal is Rm2, and a resonance wavelength of the semiconductor member is Rs.