This paper aims to research into the expression of thehabitual aspect in Korean. Habitual aspect has been contained to theaspectual categories in grammar. In Comrie(1976), the aspectualcategories are divided into Perfective and Imperfective and Habitualis contained to the Imperfective as a subordinate constituent. InEnglish, there is a past habitual marker like ‘used to’, while it isdifficult to find whether the habitual aspect can be expressed or notin Korean. In preceding researches, it is reported that the ‘-ko iss-’can be expressed to the habitual aspect. However it needs todistinguish the habitual aspect to the iterative that can be expressedby the punctual verbs. If the punctual verbs combine with theprogressive ‘-ko iss-’ in Korean, the meaning of the expression canbe interpreted as the constraint frequency. Though the habitualmeaning is same the iterative as the repetition of a situation, there isa difference to the time span between them. The ‘-ko iss-’ expressesthe iterative situation that is a constraint period of time; however thehabitual expresses the iterative situation that is an extended period oftime as a whole period. Meanwhile, the ‘-kon ha-’ can be interpretedto the iterative as a contextual meaning in Korean, so it can be dealtwith the habitual aspect like ‘used to’ in English. However there aresome differences between them. The ‘-kon ha-’ describes an iterativesituation as an incidental property of time; however the ‘used to’expresses an iterative situation as a characteristic feature of a wholeperiod. As a result, the ‘-kon ha-’ could be regarded as an iterativeaspect marker in Korean, it might be developed to the habitualmarker via the grammaticalization