It is not easy to know shearing resistance parameters c_d and ∅_d of compacted gravelly soils in field because of difficulty in getting the undisturbed samples for the laboratory test and also in performing the in situ shear test. In order to estimate shearing resistance parameters c_d and ∅_d of compacted gravelly soils in field from shear test of compacted soils in laboratory, the authers carried out shear tests (∅=150mm, h=100mm) with change of the gradation and the maximum grain size of compacted soils, and compared with the results of direct shear test in field using the 300mm×300mm×180mm shear box. From a series of laboratory tests using Samples I (cut off larger particles simply) and Samples II (replaced larger gravel-particles with smaller gravel-particles of the same weight), it is known that in situ strength parameters c_d and ∅_d of gravelly soils can be estimated reasonably by laboratory tests with a few kinds of samples I.