Decomposition of cyclohexane cations induced by intense femtosecond laser fields at the wavelength of 800 nm is investigated by ion-trap time-of-flight mass spectrometry in which cyclohexane cations C6H12 (+) stored in an ion trap are irradiated with intense femtosecond laser pulses and the generated fragment ions are recorded by time-of-flight mass spectrometry. The various fragment ion species, C5Hn (+) (n = 7, 9), C4Hn (+) (n = 5-8), C3Hn (+) (n = 3-7), C2Hn (+) (n = 2-6), and CH3 (+), identified in the mass spectra show that decomposition of C6H12 (+) proceeds efficiently by the photo-irradiation. From the laser intensity dependences of the yields of the fragment ion species, the numbers of photons required for producing the respective fragment ions are estimated.