The present invention provides an electroless gold plating bath having excellent plating bath stability without containing a cyanide compound under long term plating bath heating time. An electroless gold plating bath of the present invention solving above problems includes: a water-soluble gold salt; a reducing agent; and a phosphine compound represented by a following formula (1) wherein R1, R2, and R3 represent identically or differently either a phenyl group, or an alkyl group having 1 to 5 carbons, and at least one of the phenyl group or the alkyl group is substituted by a sulfonate group or its salt, a cyano group, or a carboxy group or its salt.