Neutral carbon clusters C-n (n=1-30) produced along with ionic clusters in laser vaporized graphite are studied under high vacuum by combined use of time-of-flight (TOF) mass spectroscopy and one photon ionization with a photon energy of 10.5 eV. The TOF mass distribution pattern shows intensification of the C4n+2 (n greater than or equal to 2) clusters more clearly than the previous work by Kaizu [J. Chem. Phys. 106, 9954 (1997)] who employed the same 10.5 eV photon but photoionized the neutral clusters generated by laser vaporization of graphite in helium buffer gas. The intensification is attributed to the intrinsic stability of the C4n+2 (n greater than or equal to 2) neutral clusters, probably due to the monocyclicity. Two different line shapes of the mass spectral peak are observed for one and the same cluster size. The line shape with a tailing toward longer flight times is associated with the neutral clusters produced by relatively slow fragmentation of larger clusters (n much greater than 30) followed by autoionization of the fragmented clusters. The other sharp line shape is associated with prompt ionization by the 10.5 eV photon. It is concluded that only the electronically excited neutral clusters are ionized for n less than or equal to 5 whereas the clusters with n > 5 are ionized irrespective of their electronic state.