Parent report can provide valuable informations on early child language development. In this paper we introduced the first Japanese version of Early Laguage Development Inventory adapted from MacArthur Communicative Development Inventorles (Fenson et al.,1991) and examined the internal consistency for each scale through 670 data of the children from the age of 8 months to 36 months. The items with low occurrence percentage and low corrected item-total correlations were found. The scales of 'First communicative gestures' and Games and routines' were combined and factor analyzed. Two factors of "Interactive acts" and "Declarative acts" were extracted. We will revise this inventory dividing into two forms-the infant from (8-20 months) and toddler from-on the basis of the results of the present study in the next step.