User authentication method and electronic device supporting the same

A user authentication method for an electronic device, the method comprising:

• detecting a content execution event;
• confirming an authentication level of content requiring iris authentication among a plurality of authentication methods, based on the detected content execution event;
• acquiring an appearance image through a camera unit;
• extracting valid regions related to an iris of a user from the acquired appearance image;
• re-acquiring the appearance image when the valid regions do not include preset certain iris regions of the user;
• and
• performing authentication of the user by comparing iris authentication reference information related to the confirmed authentication level with the extracted valid regions.