This paper was motivated by the difficulty Japanese students of Korean experience in learning the correct usage of the converb <hago>, <haeso>. As I observed by the author and mentioned in an earlier paper (Chung Hyunsuk, 1996), certain verbs fall generally into mode category when combined with <hago>. These include: verbs denoting possession, or conveyance, e.g. ‘grasp’ or ‘carry on one’s back’, ‘verbs’denoting conveyance of the subject by an object, e.g.‘ride a vehicle’, some reflexive verbs, e.g.‘close one’s eyes’, ‘bend one’s neck’, but excluding repetition verbs. I have also noticed that these three groups of verbs seldom appear combined with <haeso> in actual linguistic situations, although this combination is possible. This evident difference in usage between <hago> and <haeso> has hitherto not been researched in any great detail. The purpose of this paper is to elucidate this area(of korean grammar). Indeveloping this line of research, standard basic language situations are analysed with regard to usage of these two converbs. Model texts are supplemented where necessary by additional examples of converbs, Model texts are supplemented where necessary by additional examples of converb usage. In order to have an objective point of view, I tried to ask the opinions about these examples of many peple whose native tongues are other than korean. This methodological approach may be said to be characteristic of this paper. In chapter 2, I have made it clear that in contemporary Koran, those groups of verbs which fall into mode category when combined with <hago>, will express “means and method” or “cause and reason” when combined with <haeso>. It is meaning of the verb in such combinations that determines reason of the succeeding actions of conditions. Converbs <hago> and <haeso> differ in the way they effect the aspectual character of preceding verbs. Thus, in the sentences where the three groups of verbs are combined with <hago>---the finishing of the actions of the preceding verbs will naturally lead to the actions in the succeeding clause, and for this reason---any word may be freely used in the succeeding clause. In the sentences where the verbs are combined with <haeso>, the words used in the succeeding clauses may be subject to restriction. Thus, <hago> appears much oftner than <haeso> in the actual linguistic usage. It is inevitable that linguistic stydy should sometimes fall into arbitrary interpretation if it is done only with the student’s own examples. On the other hand, if it is only referred to linguistic materials, it will tend only to mention one phenomenon and nothing more. As I have hitherto mentioned, I noticed one linguistic fact which shows statistically remarkable difference and tried to explain why such difference occurs, by using both linguistic materials and examples. However, this paper only deals with three groups of verbs which fall in mode category when combined with <hago>. Therefore, it deals with only one aspect of one linguistic fact, leaving much to be done in the future.