My blood pressure is over 140/80 at the hospital, but it's lower at home. What should I do?

When I check my blood pressure at the hospital, it often goes over 140/80, but when I check my blood pressure at home, it comes out around 120/70.

What blood pressure level should I manage?

A few days ago, I measured my blood pressure with an automatic blood pressure monitor in the hospital hallway, and I was surprised when it came out to 140/85mmHg.
But when I come home and measure it again in a stable state, it always comes out around 120/70mmHg.

Is it okay for me to have high blood pressure only at the hospital? What blood pressure standards should I follow?