Apex domains cannot have CNAME records.
Question and response
Question
dig mineo.jp. NS
Answer
mineo.jp. 4 NS a10-65.akam.net.
mineo.jp. 4 NS a22-65.akam.net.
mineo.jp. 4 NS ns7.eonet.ne.jp.
mineo.jp. 4 NS ns1.eonet.ne.jp.
mineo.jp. 4 NS a7-66.akam.net.
mineo.jp. 4 NS a3-67.akam.net.
mineo.jp. 4 NS a1-232.akam.net.
mineo.jp. 4 NS a18-67.akam.net.
Authority
The response has no authority records.
Additional
ns1.eonet.ne.jp. 4 A 61.122.241.177
ns7.eonet.ne.jp. 4 A 60.56.0.134
a3-67.akam.net. 3 A 96.7.49.67
a18-67.akam.net. 4 A 95.101.36.67
a3-67.akam.net. 3 AAAA 2600:1408:1c:0:0:0:0:43
a18-67.akam.net. 4 AAAA 2600:1480:4800:0:0:0:0:43
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0