Osakako Subway Station has coin lockers?

I plan to travel with my small suitcase to Osakako Subway Station on the Chuo subway line from JR Bentencho Station Monday, December 10, 2018.

From Osakako I will be walking to the Kaiyukan Aquarium and therefore would like to leave my small suitcase in a coin locker at Osakako Station. I would appreciate any information on whether Osakako Station has coin lockers and their cost. Thank you for any information.

Information on coin lockers (with sizes and fees) is given on the Kaiyukan website.
http://www.kaiyukan.com/language/eng/information.html

(Coin lockers at railway stations might be removed.)

The buildings of JR and subway Bentencho Stations
are connected by a pathway.
Subway Bentencho Station is (not under but) above the ground.
The subway concourse is on the 3rd floor,
and the JR concourse is on the 2nd floor.
https://www.jr-odekake.net/eki/premises.php?id=0620504
https://www.osakametro.co.jp/station-guide/C/c13/

Thank you "omotenashi" for the web links. I looked through them and decided it may be best to leave my small suitcase at JR Bentencho station (if they have lockers) as I need to return there after visiting Kaiyukan Aquarium in order to catch the JR trains to Wakayama. Otherwise, I'll leave the suitcase at the lockers at the Bentencho subway station as shown in one of the maps you provided.

I couldn't find any information on whether JR Bentencho station has coin lockers or a luggage holding place. If you know that information, I will greatly appreciate it. Thank you again.

Check this out:
https://locker1.exblog.jp/25169299/

Thank you for the web link showing the lockers. I used the Google translate feature as I can't read Japanese, but it appears from the pictures that most if not all JR stations around Osaka have lockers available. Once I get to JR Bentencho station I'll inquire about the coin lockers there. Thanks again.

Most coin lockers are up to around 35 centimeters in width.
Please make sure your luggage piece is not too big.

In the map of (JR) Bentencho Station
you see two blue-and-white pictogram marks
(of a key above a bag) for coin lockers,
one each inside and outside the south ticket gates.
https://www.jr-odekake.net/eki/premises.php?id=0620504
A similar pictogram mark is seen on the following webpage.
http://pictogrambox.com/Download/pdf755.html

You can go between the JR and subway outer concourses
by the elevator shown at the upper right of this map.