How to give access permission to Junction Object in salesforce?

Suppose i have Junction object "jobj" (for cusobj1 and cusobj2).
and I have Role Hierarchy, as folllowing :
Admin ---- > Center Head --- > User

1. When I set OWD as "Private" for cusobj1 and cusobj2 then no any data is visible to "User". Not even self data.

2. When I set OWD as "Public Read/write" for cusobj1 and cusobj2 then all data is visible to "User". Data of admin too.

I want to show only User's data.