Is this person interested in me??

The guy in question (Rob) apparently fancies me according to my workmate. He comes to our office about once every couple of weeks. He always makes a point of speaking to me and asking me questions about my life. One time I was chatting to a male colleague, (Dan) and he came up and sat fairly close facing me. He looked down at first then he started glancing at me with a smirk on his face. He chatted to Dan about my boyfriend this other guy stood up and walked over to Dan. He was facing me and cut into the conversation saying he wanted to talk to me (obviously alone) He winked and smiled and couldn't wait to get me out the room. Once out though he seemed more distant and didn't really say what he wanted me for. It seemed quite urgent but then nothing was said. Another time he was raving to my boss about me and how good my work was, how brainy I was and that I should be studying for a degree or something.