opposite number

Your 'opposite number' in another company is the person who does the same job as you.

If you could give me the contact details of my opposite number at your company, I'll arrange a meeting.

opposite number
〈主に英〉〔他の組織において自分と〕対等の地位［職位］にいる人、〔他国の〕対応物

A person who holds a position in an organization or system corresponding to that of a person in another organization or system; a counterpart: 

a person holding an equivalent and corresponding position on another side or situation

 a person or thing having the same function or characteristics as another