$ sudo vi /etc/php-fpm.d/www.conf
----
php_admin_value[error_log] = /var/log/php-fpm/www-error.log
php_admin_flag[log_errors] = on
↓
php_value[error_log] = /var/log/php-fpm/www-error.log
php_flag[log_errors] = on
ini_set("error_log", ERROR_LOG_PATH);