Abstract: The present invention pertains to a drug available for long-term continuous administration for preventing or treating glaucoma or ocular hypertension, said drug showing no decrease in efficacy during long-term administration and exhibiting a stable ocular hypotensive effect. The present invention pertains to a therapeutic agent for glaucoma or ocular hypertension that is to be continuously administered for a long period of time, said drug comprising an Rho kinase inhibitor, more specifically, to a therapeutic agent comprising an Rho kinase inhibitor for treating glaucoma or ocular hypertension in a patient suffering from glaucoma or ocular hypertension who has been administered with a therapeutic agent comprising the Rho kinase inhibitor for treating glaucoma or ocular hypertension continuously over a definite period of time and needs a further enhanced ocular hypotensive effect.