Authentication apparatus and prism member for authentication

An authentication method using an authentication apparatus, said authentication apparatus comprising a first prism member, an imaging unit, and a visible light source that radiates visible light to a living body, wherein:

• said first prism member has a substantially trapezoidal shape with at least one side face thereof formed in an expanded shape from a living body authentication face against which an authentication portion of said living body is put, toward an imaging face that is parallel to said living body authentication face,
• said visible light source is disposed below said imaging face and near a side of an expanded side of said imaging face, and
• said imaging unit is disposed below said imaging face,
• said authentication apparatus further comprising:
• a second prism member, wherein said living body authentication face of said first prism member is an imaging face of said second prism member, and said imaging face of said first prism member is a living body authentication face of said second prism member;
• an infrared light source;
• and
• a second imaging unit, wherein:
• said first prism member and said second prism member are disposed so that a reflection face of said first prism member and a reflection face of said second prism member are opposed to each other, and
• said second imaging unit is disposed below said imaging face of said second prism member,
• the authentication method comprising:
• radiating infrared light to an authentication portion of said living body, and
• capturing, by said second imaging unit, reflected light in which said radiated infrared light is reflected by said second authentication portion of said living body.