12CO (J=1−0) emission has been detected in the extremely extinguished galaxy NGC4418 with a 15″ beam on the 45-m telescope at the Nobeyama Radio Observatory. The inferred molecular mass is 4 108 MO at a distance of 25 Mpc. The CO line profile is single peaked with the FWHM of 85 km/s, suggesting that molecular clouds highly concentrate towards the center. For the column density estimated from these observations to be consistent with the extinction value 55 < Av < 120 derived from the 10μm silicate absorption by Roche et al (1986), most of the clouds should be confined within a central region of 3.8″ (500pc) in diameter, through which beam Roche et al detected the 10 and 20μm fluxes comparable to the IRAS ones.