As a part of field test series, the effect of sampling methods on the unconfined compression strength were investigated. Test results are summarized as follows:
　1) Foild sampling reduced the strength of the sample as much as 10～20%.
　2) The advantage of P.H.R.I.-61 Method was restricted to the sample in the range of 10 cm from the lower end of the tube, and, as a whole, no appreciable difference from the ordinary method was observed. Therefore, the ordinary pulling-out method may be enough is practice, considering the complicated operations for the former.
　3) As for the method of penetration, a continuous high speed (20 cm/sec) of uniform penetration gives the least disturbed sample.