A Study to Evaluate Efficacy and Safety of CS-3150 in Japanese Type 2 Diabetic Subjects With Microalbuminuria

Inclusion Criteria: * Subjects with type 2 diabetes mellitus * Male or female subjects aged 20 years or older at informed consent * Subjects with urinary albumin to creatine ratio (UACR) ≥ 45 mg/g Cr and \< 300 mg/g Cr * Estimated glomerular filtration rate by creatinine (eGFRcreat) ≥ 30 mL/min/1.73 m\^2 * Subjects treated with angiotensin-converting enzyme inhibitor (ACEi) or angiotensin receptor blocker (ARB) for at least 3 months prior to treatment period Exclusion Criteria: * Type 1 diabetes * HbA1c (NGSP) \>=8.4% * Secondary glucose intolerance * Subjects diagnosed with non-diabetic nephropathy * Nephrotic syndrome * Secondary hypertension or malignant hypertension * Serum potassium level in any of the following categories: For subjects with eGFRcreat of ≥ 45 mL/min/1.73 m\^2, serum potassium level of \< 3.5 mEq/L or ≥ 5.1 mEq/L; For subjects with eGFRcreat of ≥ 30 mL/min/1.73 m\^2 and \< 45 mL/min/1.73 m\^2, serum potassium level of \< 3.5 mEq/L or ≥ 4.8 mEq/L