To investigate the diurnal change of intraocular pressures(IOP) and compare of $Tono-pen^{XL}$ and Schi$emptyset$tz tonometer, we measured the IOP in clinically normal eyes of dogs. To estimate the diurnal change of IOP, the measurements of IOP were taken with $Tono-pen^{XL}$ in 44 normal canine eyes. Two physicians measured the IOP through the central cornea and limbal cornea. To compare of two tonometers, a physician measured the IOP with both $Tono-pen^{XL}$ and Schi$emptyset$tz (7.5 g) tonometer in 23 clinically normal eyes of dogs. Mean of lOP was 26.51 $pm$ 6.91 mmHg and IOP was highest as 30.65 mmHg at a.m. 10, but not significantly different within physicians and corneal regions (p > 0.05). Correlation coefficient within two tonometers was too low.