The Black pine bast scale, Matsucoccus thunbergianae is one of the most serious in black pine, Pinus thunbergii forests in Korea. Since this pest was first reported in Goheung, Korea in 1963, which is gradually spread into neighboring regions and now occurs in many regions of the southern and eastern part of the Korean peninsula. The monitoring for distribution of M. thunbergianae was able to observed by naked eye egg sacs and pupa of male on the host until now. Therefore, this monitoring was very difficult in the low density of M. thubergianae. This experiment was conducted to use simple and practical moving cross-shaped flat trap for monitoring of M. thunbergianae. The monitoring of M. thunbergianae using the device was carried out to southern regions of the Korean peninsula. The first emergence of male showed mid. March in Namhae and late march in Busan, Jinju and Pohang. The peak of emergence showed late March in Namhae and early April in the other regions. When the number of M. thunbergianae intermediate nymph showed 58~59, 11~44 and 8~25 on 39.25 ㎠ bark area of the black pine, Pinus thubergii for 1 week, the number of captured its male adult was 58~83, 67~488 and 1~55 on the moving cross-shaped flat trap (10× 13㎝), respectively. The low density of M. thunbergianae was some few the number of capture, but there were no significant difference in its high density. Also, the number of captured its male adult was no significant in the different color (yellow, red, white and blue) of the moving cross-shaped flat trap.