A solution of a gallium phthalocyanine contains a compound of formula (1) and a gallium phthalocyanine of formula (2), H2N—CH2—R1—CH2—NH2  (1) wherein R1 represents a single bond, or a substituted or unsubstituted alkylene group having 1 to 10 main-chain carbon atoms, a substituent of the substituted alkylene group is an alkyl group having 1 to 3 carbon atoms, an alkyl group having 1 to 3 carbon atoms and being substituted with an amino group, or a hydroxy group, one of the carbon atoms in the main chain of the alkylene group may be replaced with an oxygen atom, a sulfur atom, or a bivalent group represented by the formula —NR2—, and R2 represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkyl group having 1 to 3 carbon atoms and being substituted with an amino group, and wherein X1 represents a chlorine atom or hydroxy group.