A method for packing a solid catalyst is provided, whereby the pressure loss of a reaction tube packed with the catalyst can be reduced.The method is characterized in that prior to packing a solid catalyst in a reactor, the solid catalyst is sieved to remove a cracked catalyst. For example, sieving is carried out against a solid catalyst of a columnar or cylindrical shape having an outer diameter A being larger than the length B in the axial direction by using a sieve having a sieve mesh with a width C satisfying the condition of A>C>B and a length being at least the width, or against a solid catalyst of a columnar or cylindrical shape with an outer diameter A being from 1 to 0.5 time the length B in the axial direction by using a sieve having a sieve mesh with a width C satisfying the condition of A>C>0.5B and a length being at least the width.