Short answer. The prosecution bears that burden. Rule 114, Section 8 states that at the hearing of a bail application filed by a person in custody for an offense punishable by death, reclusion perpetua, or life imprisonment, the prosecution has the burden of showing that evidence of guilt is strong. The accused does not have to prove weakness.
What the law says
the prosecution has the burden of showing that evidence of guilt is strong
Rule 114, Section 8 — Burden of proof in bail application. Read the full provision →
What the law says
The evidence presented during the bail hearing shall be considered automatically reproduced at the trial
Rule 114, Section 8 — Burden of proof in bail application. Read the full provision →
When the burden rule operates
The section applies at the hearing of an application for bail filed by a person who is in custody for the commission of an offense punishable by death, reclusion perpetua, or life imprisonment. Those are the charges where bail turns on the strength of the State's evidence, so the Rules dedicate a hearing to that single question. For offenses outside that band, the strength-of-evidence inquiry this section regulates is not what decides the application. The words to hold onto are evidence of guilt is strong — that, and nothing broader, is what the hearing measures.
The State proves strength; the accused proves nothing
The allocation is explicit: the prosecution has the burden of showing that evidence of guilt is strong. The accused who applies for bail does not thereby take on the job of demonstrating innocence, or of proving the case weak. If the prosecution does not carry its burden at the hearing, the premise for denying bail — a strong showing of guilt — has not been established. This matters in practice because the temptation at a bail hearing is to argue the whole case; the section frames a narrower contest, with the State as the party that must produce.
The hearing's evidence is not thrown away
Section 8 adds a second rule that surprises many litigants: The evidence presented during the bail hearing shall be considered automatically reproduced at the trial. Testimony taken at the bail stage becomes part of the trial record without being repeated. The correction mechanism is limited — upon motion of either party, the court may recall any witness for additional examination unless the latter is dead, outside the Philippines, or otherwise unable to testify. So cross-examination at the bail hearing has to be taken seriously; a witness may never be available to be recalled.
What this means for the defence
An application under this section is both an opportunity and a commitment. The opportunity: the State must show its hand early, and a family deciding whether provisional liberty is realistic learns how strong the case actually looks. The commitment: whatever emerges at the hearing follows the case to trial, so the defence examines prosecution witnesses knowing the record will stand. Counsel preparing for the hearing will want the charging papers and the evidence supporting them, since the hearing is organised entirely around whether that evidence, tested in open court, amounts to a strong showing of guilt.