Among many trace elements are found in stem of sugi (Cryptomeria Japonica D. Don), potassium (K), magnesium (Mg) and calcium (Ca), which present in a rather high quantity, can be quantitatively determined with accuracy. Therefore, these elements were extracted by some simple procedures and analyzed. From easiness of the extraction their existing state in the stem was discussed. After the wood specimen was squeezed out by a vise to collect the sap, wood blocks were sliced to cross sections of 100 μm in thickness. Subsequently, the sections were extracted with water and methanol both at 30℃, boiling water and boiling alcohol-benzene mixture and so on. The squeezed sap, the extracts and the extracted wood sections were then analyzed by atomic absorption spectrophotometry or flame emission spectrophotometry. As a result, proportion of their quantity present in the sap to that in whole stem decreased in the order of K›Mg›Ca. Additionally, all three elements were found to be lower in the heartwood than sapwood for their proportion in the sap. Besause the sum of K element squeezed out and extracted with cold water was comparable to its content for the whole stem, it can be concluded that most of the K element was extracted before the hot water extraction. The extraction rate of K element with cold methanol was rather smaller than with cold water. Though only small amounts of Mg and Ca were extracted with subsequent hot water treatment. In methanol extraction, smaller amounts of these elements were extracted compared with cold water. However, in the initial extraction stage, larger amounts of Mg and Ca were extracted with methanol than with cold water. This suggests that a part of these elements is more accessible to methanol than water. From the fact that these two elements resisted against extraction in greater extent in the heartwood than the sapwood, we first speculated that a blocking or a fixing of these took place by some nonpolar heartwood extractive components. However, since alcohol-benzene extraction did not show any difference in the extraction amount of Mg and Ca with cold water, this is not the case. Since the extraction rate of Mg and Ca was accelerated by hot water, a chemical bonding of these elements with pectic substances is conceivable. However, since the effect of the buffer solution which attacks the pectic substances was far predominant to the enzyme, the effect of the enzyme treatment could not be clarified. It is apparent that K, Mg and Ca could be easily extracted by an ion exchange in any solution which contains sodium ion.