I found the following info at Jozankei Tourist Association Official Website.
From Sapporo Sta. - Jozankei hot springs Bus Lines
From Sapporo Sta. South exit Bus terminal.
Take Jotetsu Bus bound for "Jozankei Onsen" at Gate 12 Fare : 750 yen
Time required : approximately 75 min. 2～3 buses available every hour
My query is how to get the timetable schedule for the bus?