Honestly, I am not a insect collector (which is a very popular hobby in Japan) or know the specific "beetle place" in the northern Kyushu. Although stag and rhinoceros beetles come to my house every year, they are not that many around here :) In Japan they are sold at 500 yen or so at the street shop of the festivals (for children) which means that they are somewhat hard to find for normal persons like me :)
By the way, rhinoceros beetles are very popular so that one can not specify the appropriate address for the collection in the Internet: If someone writes the info, the beetles might be caught in eccessive numbers.
Therefore I searched the Internet and found several opportunities to see the beetles around Fukuoka.
1. Stay at a Japanese onsen ryokan and take an attraction.
Mifuneyama kanko Hotel in Takeo onsen, Saga prefecture seems to be a nice Japanese inn (as judged from the Rakuten user ratings), which provides a morning tour for Kabutomushi (rhinoceros beetle) collection.
http://www.mifuneyama.co.jp/The website is in Japanese but I think you can e-mail them. I think the Hotel person will be pleased that some foreign people are interested in Japanese beetles.
info@mifuneyama.co.jp
The rates are 10000 to 15000 yen per person including dinner and breakfast, if two of you are staying on weekdays.
You can go to Takeo-onsen via train.
http://www.hyperdia.com/en/cgi/en/search.html?dep_node=HAKATA&arv_node...2. Bus tour
I found this tour, but it might not be interesting for you because this is not the "nature tour" but you can see the Kabutomushi farm.
http://www.daiichikanko.com/tour/result.htmlBus tour is 5980 yen per person and starts from JR Hakata station Chikushi-Guchi exit.
3. The insect musium
Tabira Konchu Shizen-en (Tabira Insect and nature open-air musium) in Hirado city, Nagasaki prefecture.
http://www.city.hirado.nagasaki.jp/city/info/prev.asp?fol_id=3098They have rhinoceros beetles in their field, but I am not sure whether you can see them in the opening hours (900-1700) since rhinoceros beetles are hard to see in the daytime.
You can go via JR and Matsuura railway.
http://www.hyperdia.com/en/cgi/en/search.html?dep_node=HAKATA&arv_node...Anyway, are you from Taiwan? I hear insect collection is also popular in Taiwan.