Step 1: Nature of account.
Debenture application money is collected from applicants, and until allotment, it is considered as liability of the company towards applicants.
Step 2: Account type.
Personal Account → accounts related to persons or entities to whom the company owes money.
Step 3: Conclude.
Hence, Debenture Application A/c is a Personal A/c.
Final Answer:
\[
\boxed{\text{Personal A/c}}
\]