The wettabilities of nylon 6 fiber were investigated in terms of the heat of wetting and the contact angle. The heat of wetting of nylon 6 fiber in water was measured at the range of 2$0^{circ}C$ to 7$0^{circ}C$, using an adiabatic calorimeter, and the advancing contact angle was measured using a vertical plate method. The following results were obtained. 1) The heat of wetting and the advancing contact angle of nylon 6 fiber in water decreased as the temperature increased. The curve breaking was observed at around 38$^{circ}C$, which was considered the transition temperature of nylon 6 fiber. The temperature coefficient of the contact angle showed negative value of about 0.31 deg./$^{circ}C$. 2) The heat of wetting and contact angle of nylon 6 fiber increased as the surface tension of water-ethanol mixture increased. 3) The heat of wetting of nylon 6 fiber treated with antistatic agents slightly decreased compared with untreated fiber.