Is the guy who plays Snape in Harry Potter same one orange advertisements?

You're likely thinking of Alan Rickman, who played Severus Snape in the Harry Potter films. However, he was not the actor in those orange advertisements.

The actor you're thinking of is David Mitchell, who is known for his comedic roles in shows like "Peep Show" and "Black Books." He's also the face of the popular Orange mobile phone company advertising campaign.

So, while both are talented British actors, they are different people.