A process of preparing a telechelic polyolefin is disclosed by performing steps 1a, 2, and 1b in this order in the presence of an olefin polymerizing catalyst and subsequently performing step 3 if necessary. Step 1a involves reacting the olefin polymerizing catalyst with a polar-group-containing olefin (C). Step 2 involves reacting the resultant compound of step 1a with at least one olefin (D) selected from ethylene and olefins having 3 to 20 carbon atoms n times wherein n is an integer of 1 or more, provided that when n is an integer of 2 or more, the olefins (D) used in the respective contact operations are different in kind or composition. Step 1b involves reacting the resultant compound of step 2 with the same or different polar-group-containing olefin (C). Step 3 involves chemically converting the Y′ group in the general formula (II) to a different group.