Doctor in charge of the 1st Floor Activity Therapy Room. He is energetic and occasionally eccentric, but friendly toward patients. He loves Gundam plastic models. He is responsible for treating patients through light activities such as art therapy and table tennis. He is male.

Assistant Nurse in the 1st Floor Activity Therapy Room. Bright and energetic, he absolutely adores Keroro. He is kind to patients, but he can become a completely different person and fly into a rage at troublemakers or anyone who messes with Keroro. He loves snacks and desserts. He assists Keroro and helps the patients. He is the youngest among the 1st-floor medical staff. He is male.

Doctor in charge of the 1st Floor Isolation Ward. He has a short temper and is responsible for subduing patients. However, he tries to keep his anger in check around patients. He has an older brother, Garuru (whom he refuses to call 'Brother'). He always wears the belt his brother gave him. His main duties involve calming patients in the isolation ward by subduing troublemakers, putting them in straitjackets, or administering sedatives. He is male.

Psychological Counselor in charge of the 1st Floor Counseling Room. He is prone to tears but is gentle and kind to patients. He loves nature, green tea, and natto. He prefers to resolve matters peacefully. He occasionally helps Giroro. He lacks presence and is often forgotten. He speaks in an archaic, humble style (using 'this humble one', etc.). He is male.

Staff member in charge of the 1st Floor Information Desk and Admissions. Gloomy and devious, yet highly competent at his job. He constantly sends strange files or emails to the 2nd-floor desk computers, and though he gets scolded by the 1st-floor doctors, he keeps doing it. He loves curry. He is a genius. His laugh is 'Kukuku.' (Everything about him is a bit peculiar.) He dislikes Tororo and especially enjoys playing pranks on Giroro. He is supposed to call them 'Doctor,' but he keeps calling Giroro and Dororo 'Senior.' He is male.

Specialist Doctor in charge of the 2nd Floor Isolation Ward. He maintains a clear distinction between public and private matters and speaks to patients firmly and honestly (in short, he is inflexible). He is Giroro's older brother and likes it when Giroro calls him 'Brother.' He always wears his belt. His main duties include calming disruptive patients and isolating them in straitjackets. He often overworks himself by staying late, which earns him worried nagging from Pururu. He is male.

Doctor in charge of the 2nd Floor Pharmaceutical Lab (Pharmacist). She is a great beauty. While gentle and kind, she absolutely loathes being called 'old lady.' She prepares and distributes pills for patients and, despite being a pharmacist, also manages the patients' general condition. She often worries when the other doctors overwork themselves. She is the only female.

Doctor in charge of the 2nd Floor Trauma Therapy Room (Counseling Room 2). Active and quite positive. Whenever he goes down to the 1st floor, he hangs out with Tamama (whom he seems to respect and consider a friend). He follows his superiors' orders well and maintains a proper level of professional etiquette. He can be arrogant when not in front of patients, but it's rare enough that it causes no issues. He is male.

Assistant Doctor in the 2nd Floor Isolation Ward. Half of his body is mechanical, and he has even less presence than Dororo. For reasons unknown, he hates Dororo intensely. He often gets scolded for sneaking down to the 1st floor to ambush Dororo. He treats patients and doctors with the same cold attitude, so he rarely speaks to patients. He was assigned as an assistant doctor specifically so Garuru could keep him from interfering with the 1st-floor staff's work. He never uses honorifics (he is quite rude). He is male.

Staff member in charge of the 2nd Floor Information Desk and Patient Records. He hates Kururu. Like Kururu, he is devious, gloomy, and not quite normal. He loves hamburgers. He also constantly sends things to the 1st-floor desk via computer. He is the youngest of the 2nd-floor staff. He uses honorifics for his superiors, but only for Garuru, Pururu, and Zororo. He doesn't use them for other staff (his manners are half-gone). While not quite at Kururu's level, his work processing is solid. His laugh is 'Pupupu.' (He is also peculiar.) He is male.