A new field shear test apparatus was developed in order to obtain the strength parameters of solpe soils. From the test result obtained on soils at 9 sites, the following conclusions were shown. (1) the shear strengths of undisturbed soil samples with an original grain size distribution could be determined using this apparatus. (2) The field shear behaviors of the soil samples were affected by heterogeneity. (3) The field shear tests gave smaller internal friction angle were and larger cohesion than the box shear tests.