Near-infrared polarimetric imaging observations toward the Galactic center have been carried out to examine the efficiency and wavelength dependence of interstellar polarization .
A total area of about 5.7 deg ^ { 2 } is covered in the J , H , and K _ { S } bands .
We examined the polarization efficiency , defined as the ratio of degree of polarization to color excess .
The interstellar medium between the Galactic center and us shows the polarization efficiency lower than that in the Galactic disk by a factor of three .
Moreover we investigated the spatial variation of the polarization efficiency by comparing it with those of color excess , degree of polarization , and position angle .
The spatial variations of color excess and degree of polarization depend on the Galactic latitude , while the polarization efficiency varies independently of the Galactic structure .
Position angles are nearly parallel to the Galactic plane , indicating the longitudinal magnetic field configuration between the Galactic center and us .
The polarization efficiency anticorrelates with dispersions of position angles .
The low polarization efficiency and its spatial variation can be explained by the differences of the magnetic field directions along the line-of-sight .
From the lower polarization efficiency , we suggest a higher strength of a random component relative to a uniform component of the magnetic field between the Galactic center and us .
We also derived the ratios of degree of polarization p _ { H } / p _ { J } = 0.581 \pm 0.004 and p _ { K _ { S } } / p _ { H } = 0.620 \pm 0.002 .
The power law indices of the wavelength dependence of polarization are \beta _ { JH } = 2.08 \pm 0.02 and \beta _ { HK _ { S } } = 1.76 \pm 0.01 .
Therefore the wavelength dependence of interstellar polarization exhibits flattening toward longer wavelengths in the range of 1.25 - 2.14 \micron .
The flattening would be caused by aligned large-size dust grains .