We present the first imaging circular polarimetry of the anomalous X-ray pulsar ( AXP ) 4U 0142+61 at optical wavelengths . The AXP is the only magnetar that has been well studied at optical and infrared wavelengths and is known to have a complicated broad-band spectrum over the wavelength range . The optical polarimetric observation was carried out with the 8.2-m Subaru telescope at I-band . From the observation , the degree of circular polarization V was measured to be V = 1.1 \pm 2.0 % , or |V| \leq 4.3 % ( 90 % confidence ) . The relatively large uncertainty was due to the faintness of the source ( I = 23.4 –24.0 ) . Considering the currently suggested models for optical emission from magnetars , our result is not sufficiently conclusive to discriminate the models . We suggest that because linear polarization is expected to be strong in the models , linear polarimetry of this magnetar should be conducted .