A polycarbonate diol comprising repeating units represented by the following formula (A) and a terminal hydroxy group. It is characterized in that 60-100 mol % of the repeating units represented by the formula (A) are repeating units represented by the following formula (B) or (C), the amount of the repeating units represented by the formula (B) is 10-50 mol %, excluding 50 mol %, based on the total amount of the repeating units represented by the formula (A), and the polycarbonate diol has a terminal primary OH ratio of 95-98.5%. (A) (In the formula, R represents a C2-12 divalent aliphatic or alicyclic hydrocarbon.)