Charge inversion mass spectra of C2H2+ ions produced by electron impact from HC=CH and CH2=CCl2 were measured using K and Cs targets. Clear differences in the charge inversion spectra between HC=CH and CH2=CCl2 indicate that the C2H2+ ion formed from CH2CCl2 is H2C=C+. The lifetime of H2C=C+. is found to be longer than 8.5 mu s, and the state is proposed to be the B-2(1) ground- state rather than the (4)A(2) state.