The quadrupole interaction of high-spin isomers in ¹⁹³Pb implanted into solid Hg cooled at a temperature T = 170 K has been investigated by the time-differential perturbed g\gamma -ray angular-distribution method. Spectroscopic quadrupole moment values of |Q_s | = 0.22(2)\vert Q_{\rm s} \vert = 0.22(2) eb and 0.45(4) eb have been deduced for the 21/2^- and 33/2 ⁺ three-neutron states, respectively. A much higher value |Q_s | = 2.84(26)\vert Q_{\rm s} \vert = 2.84(26) eb has been determined for the 29/2^- isomer, the band head of a magnetic rotational band.