This study aimed to identify the understanding of managers of family health units that do not count on CAPSij (Child and Youth Psychosocial Care Center), about child and adolescent mental health, and their perception of the understanding of the team about child and adolescent mental health. This is qualitative descriptive-exploratory research, based on the theoretical reference of Public Health Policies, Mental Health, Psychosocial Care for Children and Adolescents, and Primary Health Care (PHC). Twenty-one Primary Care professionals participated, who were managers of Family Health Units linked to three municipalities in the State of Sao Paulo, of different dimensions. Participants were interviewed based on semi-structured scripts. The interviews were recorded, transcribed, and analyzed with a technique of the Collective Subject Discourse (CSD). Some of the results showed: (a) the belief of the participants that the family, economic and social experiences of children and adolescents in their life contexts directly affected their mental health; (b) the failure to identify cases of child and adolescent mental health by the managers of the participating units; (c) managers' divergent perception of the team's understanding of the child and adolescent mental health. Based on the results, it is suggested that if the strengthening of matriculation and/or continuing education strategies are planned in a contextualized way according to the territories can be effective to support mental health care actions in PHC for those municipalities with less human and institutional resources.