Gas separation membrane, method of producing gas separation membrane, gas separation membrane module, and gas separator

A gas separation membrane which satisfies any one of the following Conditions 1, 3, and 4,

• Condition 1:
• a gas separation membrane which has a resin layer containing a compound having a siloxane bond, in which the resin layer containing a compound having a siloxane bond satisfies the following Expressions 1 and 2,
• 0.9≥A/B≥0.63 Expression 1
• B≥1.7 Expression 2
• in Expressions 1 and 2, A represents an O/Si ratio that is a ratio of the number of oxygen atoms relative to the number of silicon atoms contained in the resin layer containing a compound having a siloxane bond at a depth of 10 nm from the surface of the resin layer containing a compound having a siloxane bond, and B represents an O/Si ratio that is a ratio of the number of oxygen atoms relative to the number of silicon atoms in the surface of the resin layer containing a compound having a siloxane bond,
• Condition 3:
• a gas separation membrane which has a resin layer containing a compound having a siloxane bond, in which a minimum value Si0 of the proportion of peaks of Si2+ and Si3+ to peaks of all Si in ESCA depth analysis of the resin layer containing a compound having a siloxane bond is in a range of 1% to 40%, and
• Condition 4:
• a gas separation membrane which has a resin layer containing a compound having a siloxane bond, in which positron lifetime τ3 of a third component in a case where the positron is implanted at a strength of 1 keV from the surface of the resin layer containing a compound having a siloxane bond is in a range of 3.40 to 4.20 ns.