A method of preparing an IC card, which comprises a first sheet material and a second sheet material and an adhesive agent layer between the first sheet material and the second sheet material, the adhesive agent layer having therein an IC module fixed with a moisture hardenable adhesive agent, the method comprising: a pasting step to paste the first sheet material and the second sheet material while providing the IC module between the first sheet material and the second sheet material with the moisture hardenable adhesive agent to form a pasted sheet; a first storing step to store the pasted sheet under a temperature of 10 to 30.degree. C. and a relative humidity of 20 to 80%; and a second storing step to store the pasted sheet under a temperature of 20 to 50.degree. C. and a relative humidity of 40 to 100% after the first storing step.