Provided is an image guide fiber that improves image quality while preventing a manufacturing problem. The image guide fiber according to the present disclosure has a numerical aperture NA in the range of 0.70 to 0.90. A linear thermal expansion coefficient difference Δα, which is a value obtained by subtracting a linear thermal expansion coefficient α2 at from 100 to 300 °C of clad glass, from a linear thermal expansion coefficient α1 at from 100 to 300 °C of core glass, is in the range of - 3 × 10-7 / °C to 15 × 10-7 / °C. A glass-transition temperature Tg1 of the core glass is higher than a glass-transition temperature Tg2 of the clad glass. A core occupancy area ratio is 25 % or more. A pixel density is 0.1 pixel / µm2 or more.
