Guys do like when girls approach them, but it can be a stressful experience for the shy types who aren't confident. At first he may panic and cut the conversation short, or completely miss any signals you try to send. Don't hold it against him, he could just be clueless like many of us here. OTL If all else fails, you may need to spell it out for him completely bluntly and honestly. ("I like you, I want to pursue romatic relations with you, will you go out with me", or something to that effect.)

He knows you like him but he hasn't talked to you? Please, elaborate.