Hamsters are tiny and timid creatures that have evolved as prey for bigger carnivores. When you reach down to grab the little fellow, it resembles a bird of prey swooping to catch him. You would feel nervous too!
The best way to make friends with a hamster is to offer him tasty treats from your hand, a nice fat pumpkin seed or frozen pea. Do not insist he takes it. If he is frightened, he will not have much of an appetite. Gently and calmly persist though. Do not chase him round, be patient and eventually he will come to you. Scoop him up with both hands from underneath. Lift him a little way, then set him down again. Repeat this so he will come to understand you do not want to hurt him. You need to build trust. Above all, do not drop him! Hold him over a table or on the floor, but make sure all the doors to the room you are in are closed, in case he scoots off.