Patient description: A 4 year old boy presents to the emergency room with wheezing. He has had a history of allergic rhinitis, but no history of wheezing. His mother reports that 5 hours ago patient was playing in the backyard sandbox when she heard him suddenly start coughing. The coughing lasted only moments, but he has been audibly wheezing since. Mother was concerned, because his breathing has not returned to normal, so she brought him to the ED. On exam, the child is playful and well appearing. Wheezing is heard in the mid-right chest area. O2 sats are 100% on room air.

Clinical trial eligibility criteria: eligible ages (years): 0.5-4.0,  Asthma The written informed consent must be obtained from his/her parent or legally acceptable representative. If the investigator can get the oral consent from the patient, the investigator should record so in the informed consent which is signed by his/her parent or legally acceptable representative Ethnic origin is Japanese Aged >=6 months and <=4 years at Visit 1 Male and pre-menarchial female. Pre-menarchial females are defined as any female who has yet to begin menses Patient: outpatient Diagnosis as a pediatric asthma has been made by reference to JPGL 2012 and the document which is of help as evidence should be kept as source document. As for <2 years old, children are going to be diagnosed according to an instruction as follows in JPGL2012 as a reference. There are 3 or more episodes of marked expiratory wheezing, regardless of the presence of respiratory tract infection. It is also needed to confirm that there is asymptomatic period for about a week between each episode. In addition to this finding, if there is at least one of following findings, it is more helpful to diagnose infantile asthma: At least one of parents is diagnosed with bronchial asthma by a physician (including past history); Specific immunoglobulin E (IgE) antibody for inhalation antigen is detected in at least one of parents; Diseased child is diagnosed with atopic dermatitis by a physician (including past history); Specific IgE antibody for inhalation antigen is detected in diseased child; High serum IgE level in diseased child or his/her family (serum IgE level should be determined by considering age); Eosinophils and creola bodies found in sputum (examine nasal discharge eosinophilia and peripheral blood eosinophilia); Expiratory wheezing occurs when there is no airway infection; Expiratory wheezing and labored respiration or oxygen saturation are improved after beta-2 stimulant inhalation A patient who needs to be treated with Inhaled corticosteroid (ICS)/ Long-acting beta 2 agonist (LABA) and fulfill following all conditions: At least one documented exacerbation in that the patient treated with systemic glucocorticosteroids, aminophylline dose intravenous(d.i.v) or continuous isoproterenol inhalation in the 12 months prior to Visit 1. Or a well-documented regular treatment with ICS (FP 200-400 mcg daily or equivalent) continuous use in the 12 months prior to Visit 1; The patient has not received systemic glucocorticosteroids, aminophylline d.i.v., ICS (FP>200 mcg daily or equivalent) or continuous isoproterenol inhalation within 4 weeks prior to Visit 1  A patient who has suffered from upper and lower respiratory tract infection and then received medication within 2 weeks prior to Visit 1 A patient who is diagnosed upper and lower respiratory tract infection at Visit 1. Or a patient who has or is suspected to have deep-seated mycosis or infection to which no effective antibacterial agent is available. Or a patient who is suspected to have respiratory syncytial (RS) virus infection and cannot be identified to be negative for RS virus antigen A patient who has respiratory disorder other than bronchial asthma, and the investigator judges the respiratory disorder affect the assessment of efficacy in this study A patient who has unstable liver disease or chronic stable hepatitis B receiving significant immunosuppressive agents due to risk of hepatitis B reactivation A patient who has malformation/foreign particle lodged in an airway. Or subjects who have known, pre-existing, clinically significant gastroesophageal reflux disease , endocrine, autoimmune, metabolic, neurological, renal, gastrointestinal, hepatic, haematological or any other system abnormalities that are uncontrolled with standard treatment A patient who has or is suspected to have hypersensitivity to study medications, the rescue medication or any ingredients of them A patient who has been treated with another investigational product within 1 months prior to Visit 1 or within five half-lives (t-half) of the prior investigational study (whichever is the longer of the two) As for the patients who has evaluable ECG data at Visit 1, QT interval corrected (Fridericia) for heart rate (QTc[F])>=450 milliseconds (msec). The QT interval corrected for heart rate (QTc) should be based on averaged QTc values of triplicate electrocardiograms (ECGs) obtained over a brief recording period. As for the patients who don't has evaluable ECG data at Visit 1, if the patient has known prolonged QTc>=450 msec (any correction is valid), the patient will be excluded A patient who is child in care (including foster parent system), or whom the investigator judges inappropriate for the study Randomization Criterion