| abstract |
A gas barrier film that includes at least a film base material including a polyester resin having a butylene terephthalate unit as a main constituent unit, and one or more metal oxide layers wherein the gas barrier film has a heat shrinkage rate in the machine direction (MD direction) after heating for 30 minutes at 150° C. of 0.6% or more but less than 3.0%, the heat shrinkage rate being represented by the following formula: Heat shrinkage rate={(Length before heating−Length after heating)/Length before heating}×100(%). |