# models.py class Monster(models.Model): first_name = models.CharField(max_length=255) last_name = models.CharField(max_length=255) @property def full_name(self): return self.first_name + self.last_name class MonsterSerializer(serializer.ModelSerializer) class Meta: model = Monster readonly_fields = ("full_name) # sourceでプロパティ名入れる full_name = serializer.ReadOnlyField(source="full_name", read_only=True)